Journal articles: 'PrrAB'

1

Laratta, William P., Peter S. Choi, Ivan E. Tosques, and James P. Shapleigh. "Involvement of the PrrB/PrrA Two-Component System in Nitrite Respiration in Rhodobacter sphaeroides 2.4.3: Evidence for Transcriptional Regulation." Journal of Bacteriology 184, no. 13 (July 1, 2002): 3521–29. http://dx.doi.org/10.1128/jb.184.13.3521-3529.2002.

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ABSTRACT Rhodobacter sphaeroides strain 2.4.3 is capable of diverse metabolic lifestyles, including denitrification. The regulation of many Rhodobacter genes involved in redox processes is controlled, in part, by the PrrBA two-component sensor-regulator system, where PrrB serves as the sensor kinase and PrrA is the response regulator. Four strains of 2.4.3 carrying mutations within the prrB gene were isolated in a screen for mutants unable to grow anaerobically on medium containing nitrite. Studies revealed that the expression of nirK, the structural gene encoding nitrite reductase, in these strains was significantly decreased compared to its expression in 2.4.3. Disruption of prrA also eliminated the ability to grow both photosynthetically and anaerobically in the dark on nitrite-amended medium. Complementation with prrA restored the wild-type phenotype. The PrrA strain exhibited a severe decrease in both nitrite reductase activity and expression of a nirK-lacZ fusion. Nitrite reductase activity in the PrrA strain could be restored to wild-type levels by using nirK expressed from a heterologous promoter, suggesting that the loss of nitrite reductase activity in the PrrA and PrrB mutants was not due to problems with enzyme assembly or the supply of reductant. Inactivation of prrA had no effect on the expression of the gene encoding NnrR, a transcriptional activator required for the expression of nirK. Inactivation of ccoN, part of the cbb 3-type cytochrome oxidase shown to regulate the kinase activity of PrrB, also caused a significant decrease in both nirK expression and Nir activity. This was unexpected, since PrrA-P accumulates in the ccoN strain. Together, these results demonstrate that PrrBA plays an essential role in the regulation of nirK.

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Eraso, Jesus M., Jung Hyeob Roh, Xiaohua Zeng, Stephen J. Callister, Mary S. Lipton, and Samuel Kaplan. "Role of the Global Transcriptional Regulator PrrA in Rhodobacter sphaeroides 2.4.1: Combined Transcriptome and Proteome Analysis." Journal of Bacteriology 190, no. 14 (May 16, 2008): 4831–48. http://dx.doi.org/10.1128/jb.00301-08.

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ABSTRACTThe PrrBA two-component regulatory system is a major global regulator inRhodobacter sphaeroides2.4.1. Here we have compared the transcriptome and proteome profiles of the wild-type (WT) and mutant PrrA2 cells grown anaerobically in the dark with dimethyl sulfoxide as an electron acceptor. Approximately 25% of the genes present in the PrrA2 genome are regulated by PrrA at the transcriptional level, either directly or indirectly, by twofold or more relative to the WT. The genes affected are widespread throughout all COG (cluster of orthologous group) functional categories, with previously unsuspected “metabolic” genes affected in PrrA2 cells. PrrA was found to act as both an activator and a repressor of transcription, with more genes being repressed in the presence of PrrA (9:5 ratio). An analysis of the genes encoding the 1,536 peptides detected through our chromatographic study, which corresponds to 36% coverage of the genome, revealed that approximately 20% of the genes encoding these proteins were positively regulated, whereas approximately 32% were negatively regulated by PrrA, which is in excellent agreement with the percentages obtained for the whole-genome transcriptome profile. In addition, comparison of the transcriptome and proteome mean parameter values for WT and PrrA2 cells showed good qualitative agreement, indicating that transcript regulation paralleled the corresponding protein abundance, although not one for one. The microarray analysis was validated by direct mRNA measurement of randomly selected genes that were both positively and negatively regulated.lacZtranscriptional andkantranslational fusions enabled us to map putative PrrA binding sites and revealed potential gene targets for indirect regulation by PrrA.

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Maarsingh, Jason D., and Shelley E. Haydel. "Mycobacterium smegmatis PrrAB two-component system influences triacylglycerol accumulation during ammonium stress." Microbiology 164, no. 10 (October 1, 2018): 1276–88. http://dx.doi.org/10.1099/mic.0.000705.

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Zhou, Li, Meng Zhao, Rachel Z. Wolf, David E. Graham, and George Georgiou. "Transcriptional Regulation of the Escherichia coli Gene rraB, Encoding a Protein Inhibitor of RNase E." Journal of Bacteriology 191, no. 21 (August 28, 2009): 6665–74. http://dx.doi.org/10.1128/jb.00344-09.

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ABSTRACT The Escherichia coli RNA degradosome is a protein complex that plays a critical role in the turnover of numerous RNAs. The key component of the degradosome complex is the endoribonuclease RNase E, a multidomain protein composed of an N-terminal catalytic region and a C-terminal region that organizes the other protein components of the degradosome. Previously, the RNase E inhibitors RraA and RraB were identified genetically and shown to bind to the C-terminal region of RNase E, thus affecting both the protein composition of the degradosome and the endonucleolytic activity of RNase E. In the present work, we investigated the transcriptional regulation of rraB. rraB was shown to be transcribed constitutively from its own promoter, PrraB. Transposon mutagenesis and screening for increased β-galactosidase activity from a chromosomal PrraB-lacZ transcriptional fusion resulted in the isolation of a transposon insertion in glmS, encoding the essential enzyme glucosamine-6-phosphate synthase that catalyzes the first committed step of the uridine 5′-diphospho-N-acetyl-glucosamine (UDP-GlcNAc) pathway, which provides intermediates for peptidoglycan biogenesis. The glmS852::Tn5 allele resulted in an approximately 50% lower intracellular concentration of UDP-GlcNAc and conferred a fivefold increase in the level of rraB mRNA. This allele also mediated a twofold increase in β-galactosidase activity from a chromosomal fusion of the 5′ untranslated region of the rne gene to lacZ, suggesting that a reduction in cellular concentration of UDP-GlcNAc and the resulting increased expression of RraB might modulate the action of RNase E.

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Seok, Jin-Sook, Samuel Kaplan, and Jeong-Il Oh. "Interacting specificity of a histidine kinase and its cognate response regulator: the PrrBA system of Rhodobacter sphaeroides." Microbiology 152, no. 8 (August 1, 2006): 2479–90. http://dx.doi.org/10.1099/mic.0.28961-0.

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Using a yeast two-hybrid assay system, it was demonstrated that the four-helix bundle of the Rhodobacter sphaeroides PrrB histidine kinase both serves as the interaction site for the regulatory domain of its cognate response regulator PrrA and is the primary determinant of the interaction specificity. The α-helix 1 and its flanking turn region within the dimerization domain (DD) of the PrrB histidine kinase appear to play an important role in conferring the recognition specificity for the PrrA response regulator on the DD. The catalytic ATP-binding domain of the histidine kinase, which functions as the catalytic unit for the phosphotransfer reaction from ATP to the conserved histidine residue in the DD, also appears to contribute to the enhancement of the recognition specificity conferred by the DD. It was also revealed that replacement of Asp-63 and Lys-113 of the PrrA response regulator by alanine abolished protein–protein interactions between PrrA and its cognate histidine kinase PrrB, whereas mutations of Asp-19, Asp-20 and Thr-87 to alanine did not affect protein–protein interactions, indicating that among the active site residues of PrrA, Asp-63 and Lys-113 are important not only in the function of PrrA but also for protein–protein interactions between PrrA and PrrB.

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6

Comolli, James C., Audrey J. Carl, Christine Hall, and Timothy Donohue. "Transcriptional Activation of the Rhodobacter sphaeroides Cytochrome c2 Gene P2 Promoter by the Response Regulator PrrA." Journal of Bacteriology 184, no. 2 (January 15, 2002): 390–99. http://dx.doi.org/10.1128/jb.184.2.390-399.2002.

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ABSTRACT Anoxygenic photosynthetic growth of Rhodobacter sphaeroides, a member of the α subclass of the class Proteobacteria, requires the response regulator PrrA. PrrA and the sensor kinase PrrB are part of a two-component signaling pathway that influences a wide range of processes under oxygen-limited conditions. In this work we characterized the pathway of transcription activation by PrrB and PrrA by purifying these proteins, analyzing them in vitro, and characterizing a mutant PrrA protein in vivo and in vitro. When purified, a soluble transmitter domain of PrrB (cPrrB) could autophosphorylate, rapidly transfer phosphate to PrrA, and stimulate dephosphorylation of phospho-PrrA. Unphosphorylated PrrA activated transcription from a target cytochrome c 2 gene (cycA) promoter, P2, which contained sequences from −73 to +22 relative to the transcription initiation site. However, phosphorylation of PrrA increased its activity since activation of cycA P2 was enhanced up to 15-fold by treatment with the low-molecular-weight phosphodonor acetyl phosphate. A mutant PrrA protein containing a single amino acid substitution in the presumed phosphoacceptor site (PrrA-D63A) was not phosphorylated in vitro but also was not able to stimulate cycA P2 transcription. PrrA-D63A also had no apparent in vivo activity, demonstrating that aspartate 63 is necessary both for the function of PrrA and for its phosphorylation-dependent activation. The cellular level of wild-type PrrA was negatively autoregulated so that less PrrA was present in the absence of oxygen, conditions in which the activities of many PrrA target genes increase. PrrA-D63A failed to repress expression of the prrA gene under anaerobic conditions, suggesting that this single amino acid change also eliminated PrrA function in vivo.

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Gomelsky, Larissa, Oleg V. Moskvin, Rachel A. Stenzel, Denise F. Jones, Timothy J. Donohue, and Mark Gomelsky. "Hierarchical Regulation of Photosynthesis Gene Expression by the Oxygen-Responsive PrrBA and AppA-PpsR Systems of Rhodobacter sphaeroides." Journal of Bacteriology 190, no. 24 (October 17, 2008): 8106–14. http://dx.doi.org/10.1128/jb.01094-08.

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ABSTRACT In the facultatively phototrophic proteobacterium Rhodobacter sphaeroides, formation of the photosynthetic apparatus is oxygen dependent. When oxygen tension decreases, the response regulator PrrA of the global two-component PrrBA system is believed to directly activate transcription of the puf, puh, and puc operons, encoding structural proteins of the photosynthetic complexes, and to indirectly upregulate the photopigment biosynthesis genes bch and crt. Decreased oxygen also results in inactivation of the photosynthesis-specific repressor PpsR, bringing about derepression of the puc, bch, and crt operons. We uncovered a hierarchical relationship between these two regulatory systems, earlier thought to function independently. We also more accurately assessed the spectrum of gene targets of the PrrBA system. First, expression of the appA gene, encoding the PpsR antirepressor, is PrrA dependent, which establishes one level of hierarchical dominance of the PrrBA system over AppA-PpsR. Second, restoration of the appA transcript to the wild-type level is insufficient for rescuing phototrophic growth impairment of the prrA mutant, whereas inactivation of ppsR is sufficient. This suggests that in addition to controlling appA transcription, PrrA affects the activity of the AppA-PpsR system via an as yet unidentified mechanism(s). Third, PrrA directly activates several bch and crt genes, traditionally considered to be the PpsR targets. Therefore, in R. sphaeroides, the global PrrBA system regulates photosynthesis gene expression (i) by rigorous control over the photosynthesis-specific AppA-PpsR regulatory system and (ii) by extensive direct transcription activation of genes encoding structural proteins of photosynthetic complexes as well as genes encoding photopigment biosynthesis enzymes.

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Metz, Sebastian, Andreas Jäger, and Gabriele Klug. "In Vivo Sensitivity of Blue-Light-Dependent Signaling Mediated by AppA/PpsR or PrrB/PrrA in Rhodobacter sphaeroides." Journal of Bacteriology 191, no. 13 (April 24, 2009): 4473–77. http://dx.doi.org/10.1128/jb.00262-09.

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ABSTRACT Formation of photosynthesis complexes in Rhodobacter sphaeroides is regulated in a redox- and light-dependent manner by the AppA/PpsR and PrrB/PrrA systems. While on the one hand, blue light is sensed by the flavin adenine dinucleotide-binding BLUF domain of AppA, on the other, light is absorbed by bacteriochlorophyll signals through PrrB/PrrA. We show that much smaller quantities initiate the AppA-mediated response to blue light than the bacteriochlorophyll-mediated response.

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Ewann, Fanny, Mary Jackson, Kevin Pethe, Andrea Cooper, Nathalie Mielcarek, Danielle Ensergueix, Brigitte Gicquel, Camille Locht, and Philip Supply. "Transient Requirement of the PrrA-PrrB Two-Component System for Early Intracellular Multiplication of Mycobacterium tuberculosis." Infection and Immunity 70, no. 5 (May 2002): 2256–63. http://dx.doi.org/10.1128/iai.70.5.2256-2263.2002.

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ABSTRACT Adaptive regulation of gene expression in response to environmental changes is a general property of bacterial pathogens. By screening an ordered transposon mutagenesis library of Mycobacterium tuberculosis, we have identified three mutants containing a transposon in the coding sequence or in the 5′ regions of genes coding for two-component signal transduction systems (trcS, regX3, prrA). The intracellular multiplication capacity of the three mutants was investigated in mouse bone marrow-derived macrophages. Only the prrA mutant showed a defect in intracellular growth during the early phase of infection, and this defect was fully reverted when the mutant was complemented with prrA-prrB wild-type copies. The mutant phenotype was transient, as after 1 week this strain recovered full growth capacity to reach levels similar to that of the wild type at day 9. Moreover, a transient induction of prrA promoter activity was observed during the initial phase of macrophage infection, as shown by a prrA promoter-gfp fusion in M. bovis BCG infecting the mouse macrophages. The concordant transience of the prrA mutant phenotype and prrA promoter activity indicates that the PrrA-PrrB two-component system is involved in the environmental adaptation of M. tuberculosis, specifically in an early phase of the intracellular growth, and that, similar to other facultative intracellular parasites, M. tuberculosis can use genes temporarily required at different stages in the course of macrophage infection.

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10

Oh, Jeong-Il, In-Jeong Ko, and Samuel Kaplan. "The Default State of the Membrane-Localized Histidine Kinase PrrB of Rhodobacter sphaeroides 2.4.1 Is in the Kinase-Positive Mode." Journal of Bacteriology 183, no. 23 (December 1, 2001): 6807–14. http://dx.doi.org/10.1128/jb.183.23.6807-6814.2001.

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ABSTRACT The PrrBA two-component activation system of Rhodobacter sphaeroides plays a major role in the induction of photosynthesis gene expression under oxygen-limiting or anaerobic conditions. The PrrB histidine kinase is composed of two structurally identifiable regions, the conserved C-terminal kinase/phosphatase domain and the N-terminal membrane-spanning domain with six transmembrane helices framing three periplasmic and two cytoplasmic loops. Using a set of PrrB mutants with lesions in the transmembrane domain, we demonstrate that the central portion of the PrrB transmembrane domain including the second periplasmic loop plays an important role in both sensing and signal transduction. Signal transduction via the transmembrane domain is ultimately manifested by controlling the activity of the C-terminal kinase/phosphatase domain. The extent of signal transduction is determined by the ability of the transmembrane domain to sense the strength of the inhibitory signal received from the cbb 3 terminal oxidase (J.-I Oh, and S. Kaplan, EMBO J. 19:4237–4247, 2000). Therefore, the intrinsic (“default”) state of PrrB is in the kinase-dominant mode. It is also demonstrated that the extent ofprrB gene expression is subject to the negative autoregulation of the PrrBA system.

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Haydel, S. E., V. Malhotra, G. L. Cornelison, and J. E. Clark-Curtiss. "The prrAB Two-Component System Is Essential for Mycobacterium tuberculosis Viability and Is Induced under Nitrogen-Limiting Conditions." Journal of Bacteriology 194, no. 2 (November 11, 2011): 354–61. http://dx.doi.org/10.1128/jb.06258-11.

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Ranson-Olson, Britton, Denise F. Jones, Timothy J. Donohue, and Jill H. Zeilstra-Ryalls. "In Vitro and In Vivo Analysis of the Role of PrrA in Rhodobacter sphaeroides 2.4.1 hemA Gene Expression." Journal of Bacteriology 188, no. 9 (May 1, 2006): 3208–18. http://dx.doi.org/10.1128/jb.188.9.3208-3218.2006.

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ABSTRACT The hemA gene codes for one of two synthases in Rhodobacter sphaeroides 2.4.1 which catalyze the formation of 5-aminolevulinic acid. We have examined the role of PrrA, a DNA binding protein that is associated with the metabolic switch between aerobic growth and anoxygenic photosynthetic growth, in hemA expression and found that hemA transcription is directly activated by PrrA. Using electrophoretic mobility shift assays and DNase I protection assays, we have mapped two binding sites for PrrA within the hemA upstream sequences, each of which contains an identical 9-bp motif. Using lacZ transcription reporter plasmids in wild-type strain 2.4.1 and PrrA− mutant strain PRRA2, we showed that PrrA was required for maximal expression. We also found that the relative impacts of altering DNA sequences within the two binding sites are different depending on whether cells are growing aerobically or anaerobically. This reveals a greater level of complexity associated with PrrA-mediated regulation of transcription than has been heretofore described. Our findings are of particular importance with respect to those genes regulated by PrrA having more than one upstream binding site. In the case of the hemA gene, we discuss possibilities as to how these new insights can be accommodated within the context of what has already been established for hemA transcription regulation in R. sphaeroides.

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Mishra, Alok K., Shivraj M. Yabaji, Rikesh K. Dubey, Ekta Dhamija, and Kishore K. Srivastava. "Dual phosphorylation in response regulator protein PrrA is crucial for intracellular survival of mycobacteria consequent upon transcriptional activation." Biochemical Journal 474, no. 24 (December 6, 2017): 4119–36. http://dx.doi.org/10.1042/bcj20170596.

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The remarkable ability of Mycobacterium tuberculosis (Mtb) to survive inside human macrophages is attributed to the presence of a complex sensory and regulatory network. PrrA is a DNA-binding regulatory protein, belonging to an essential two-component system (TCS), PrrA/B, which is required for early phase intracellular replication of Mtb. Despite its importance, the mechanism of PrrA/B-mediated signaling is not well understood. In the present study, we demonstrate that the binding of PrrA on the promoter DNA and its consequent activation is cumulatively controlled via dual phosphorylation of the protein. We have further characterized the role of terminal phospho-acceptor domain in the physical interaction of PrrA with its cognate kinase PrrB. The genetic deletion of prrA/B in Mycobacterium smegmatis was possible only in the presence of ectopic copies of the genes, suggesting the essentiality of this TCS in fast-growing mycobacterial strains as well. The overexpression of phospho-mimetic mutant (T6D) altered the growth of M. smegmatis in an in vitro culture and affected the replication of Mycobacterium bovis BCG in mouse peritoneal macrophages. Interestingly, the Thr6 site was found to be conserved in Mtb complex, whereas it was altered in some fast-growing mycobacterial strains, indicating that this unique phosphorylation might be predominant in employing the regulatory circuit in M. bovis BCG and presumably also in Mtb complex.

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Bellale, Eknath, Maruti Naik, Varun VB, Anisha Ambady, Ashwini Narayan, Sudha Ravishankar, Vasanthi Ramachandran, et al. "Diarylthiazole: An Antimycobacterial Scaffold Potentially Targeting PrrB-PrrA Two-Component System." Journal of Medicinal Chemistry 57, no. 15 (July 16, 2014): 6572–82. http://dx.doi.org/10.1021/jm500833f.

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Kim, Yong-Jin, In-Jeong Ko, Jin-Mok Lee, Ho-Young Kang, Young Min Kim, Samuel Kaplan, and Jeong-Il Oh. "Dominant Role of the cbb3 Oxidase in Regulation of Photosynthesis Gene Expression through the PrrBA System in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 189, no. 15 (June 8, 2007): 5617–25. http://dx.doi.org/10.1128/jb.00443-07.

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ABSTRACT In this study, the H303A mutant form of the cbb 3 oxidase (H303A oxidase), which has the H303A mutation in its catalytic subunit (CcoN), was purified from Rhodobacter sphaeroides. The H303A oxidase showed the same catalytic activity as did the wild-type form of the oxidase (WT oxidase). The heme contents of the mutant and WT forms of the cbb 3 oxidase were also comparable. However, the puf and puc operons, which are under the control of the PrrBA two-component system, were shown to be derepressed aerobically in the R. sphaeroides strain expressing the H303A oxidase. Since the strain harboring the H303A oxidase exhibited the same cytochrome c oxidase activity as the stain harboring the WT oxidase did, the aerobic derepression of photosynthesis gene expression observed in the H303A mutant appears to be the result of a defective signaling function of the H303A oxidase rather than reflecting any redox changes in the ubiquinone/ubiquinol pool. It was also demonstrated that ubiquinone inhibits not only the autokinase activity of full-length PrrB but also that of the truncated form of PrrB lacking its transmembrane domain, including the proposed quinone binding sequence. These results imply that the suggested ubiquinone binding site within the PrrB transmembrane domain is not necessary for the inhibition of PrrB kinase activity by ubiquinone. Instead, it is probable that signaling through H303 of the CcoN subunit of the cbb 3 oxidase is part of the pathway through which the cbb 3 oxidase affects the relative kinase/phosphatase activity of the membrane-bound PrrB.

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O’Gara, James P., Jesus M. Eraso, and Samuel Kaplan. "A Redox-Responsive Pathway for Aerobic Regulation of Photosynthesis Gene Expression in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 180, no. 16 (August 15, 1998): 4044–50. http://dx.doi.org/10.1128/jb.180.16.4044-4050.1998.

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ABSTRACT To further understand the proposed signal transduction pathway involving the presumed redox proteins RdxBH andcbb 3 cytochrome oxidase in Rhodobacter sphaeroides 2.4.1, a series of mutants lacking components of both the Prr two-component activation system and thecbb 3-type cytochrome oxidase or RdxBH were constructed. We report that under highly aerobic conditions, aberrant photosynthesis gene expression and spectral complex formation typical of cbb 3- or RdxBH-deficient mutants were no longer observed when either prrA (encoding the response regulator of the Prr system) or prrB (encoding the presumed sensor kinase) was also deleted. These double-mutant strains are phenotypically identical to single-mutant PrrA and PrrB strains, suggesting that the signal(s) originating from thecbb 3 terminal oxidase affects downstreampuc and puf operon expression by acting exclusively through the Prr system. When the same double-mutant strains were examined under anaerobic dark dimethyl sulfoxide growth conditions, photosynthesis gene expression was obligatorily linked to the two-component activation system. However, photosynthesis gene expression under the same growth conditions was significantly higher in the cbb 3 mutant strain when compared to that in the wild type. Similarly, under anaerobic photosynthetic conditions the high levels of the oxidized carotenoid, spheroidenone, which accumulate in cbb 3-deficient mutants were nearly restored to normal in a PrrB− CcoP− double mutant. This observation, together with previously published results, suggests that the regulation of the CrtA-catalyzed reaction possesses both transcriptional and posttranscriptional regulatory effectors. We propose that the cbb 3 cytochrome oxidase, which by definition can interact with external oxygen, serves to control the activity of the Prr two-component activation system under both aerobic and anaerobic conditions. Although independent from thecbb 3 oxidase, the RdxBH proteins are also required for normal functioning of the Prr two-component activation system and are therefore believed to lie between thecbb 3 oxidase in this oxygen-sensing, redox signaling pathway and the Prr activation system.

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Moskvin, Oleg V., Larissa Gomelsky, and Mark Gomelsky. "Transcriptome Analysis of the Rhodobacter sphaeroides PpsR Regulon: PpsR as a Master Regulator of Photosystem Development." Journal of Bacteriology 187, no. 6 (March 15, 2005): 2148–56. http://dx.doi.org/10.1128/jb.187.6.2148-2156.2005.

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ABSTRACT PpsR from the anoxygenic phototrophic bacterium Rhodobacter sphaeroides has been known as an oxygen- and light-dependent repressor of bacteriochlorophyll and carotenoid biosynthesis genes and puc operons involved in photosystem development. However, the putative PpsR-binding sites, TGTN12ACA, are also located upstream of numerous nonphotosystem genes, thus raising the possibility that the role of PpsR is broader. To characterize the PpsR regulon, transcriptome profiling was performed on the wild-type strain grown at high and low oxygen tensions, on the strain overproducing PpsR, and on the ppsR mutant. Transcriptome analysis showed that PpsR primarily regulates photosystem genes; the consensus PpsR binding sequence is TGTcN10gACA (lowercase letters indicate lesser conservation); the presence of two binding sites is required for repression in vivo. These findings explain why numerous single TGTN12ACA sequences are nonfunctional. In addition to photosystem genes, the hemC and hemE genes involved in the early steps of tetrapyrrole biosynthesis were identified as new direct targets of PpsR repression. Unexpectedly, PpsR was found to indirectly repress the puf and puhA operons encoding photosystem core proteins. The upstream regions of these operons contain no PpsR binding sites. Involvement in regulation of these operons suggests that PpsR functions as a master regulator of photosystem development. Upregulation of the puf and puhA operons that resulted from ppsR inactivation was sufficient to restore the ability to grow phototrophically to the prrA mutant. PrrA, the global redox-dependent activator, was previously considered indispensable for phototrophic growth. It is revealed that the PrrBA and AppA-PpsR systems, believed to work independently, in fact interact and coordinately regulate photosystem development.

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Jones, Denise F., Rachelle A. Stenzel, and Timothy J. Donohue. "Mutational analysis of the C-terminal domain of the Rhodobacter sphaeroides response regulator PrrA." Microbiology 151, no. 12 (December 1, 2005): 4103–10. http://dx.doi.org/10.1099/mic.0.28300-0.

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The Rhodobacter sphaeroides response regulator PrrA directly activates transcription of genes necessary for energy conservation at low O2 tensions and under anaerobic conditions. It is proposed that PrrA homologues contain a C-terminal DNA-binding domain (PrrA-CTD) that lacks significant amino acid sequence similarity to those found in other response regulators. To test this hypothesis, single amino acid substitutions were created at 12 residues in the PrrA-CTD. These mutant PrrA proteins were purified and tested for the ability to be phosphorylated by the low-molecular-mass phosphate donor acetyl phosphate, to activate transcription and to bind promoter DNA. Each mutant PrrA protein accepted phosphate from 32P-labelled acetyl phosphate. At micromolar concentrations of acetyl phosphate-treated wild-type PrrA, a single 20 bp region in the PrrA-dependent cycA P2 promoter was protected from DNase I digestion. Of the mutant PrrA proteins tested, only acetyl phosphate-treated PrrA-N168A and PrrA-I177A protected cycA P2 from DNase I digestion at similar protein concentrations compared to wild-type PrrA. The use of in vitro transcription assays with the PrrA-dependent cycA P2 and puc promoters showed that acetyl phosphate-treated PrrA-N168A produced transcript levels similar to that of wild-type PrrA at comparable protein concentrations. Using concentrations of acetyl phosphate-treated PrrA that are saturating for the wild-type protein, PrrA-H170A and PrrA-I177A produced <45 % as much transcript as wild-type PrrA. Under identical conditions, the remaining mutant PrrA proteins produced little or no detectable transcripts from either promoter in vitro. Explanations are presented for why these amino acid side chains in the PrrA-CTD are important for its ability to activate transcription.

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Craith, Delores Nic, and Delores Ní Nic Craith. "Preab sa Cheol." Comhar 46, no. 6 (1987): 34. http://dx.doi.org/10.2307/20556270.

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Craith, Delores Nic. "Preab sa Cheol." Comhar 46, no. 8 (1987): 32. http://dx.doi.org/10.2307/20556304.

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Craith, Delores Nic. "Preab sa Cheol." Comhar 46, no. 10 (1987): 30. http://dx.doi.org/10.2307/20556344.

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Ranson-Olson, Britton, and Jill H. Zeilstra-Ryalls. "Regulation of the Rhodobacter sphaeroides 2.4.1 hemA Gene by PrrA and FnrL." Journal of Bacteriology 190, no. 20 (August 8, 2008): 6769–78. http://dx.doi.org/10.1128/jb.00828-08.

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ABSTRACT Part of the oxygen responsiveness of Rhodobacter sphaeroides 2.4.1 tetrapyrrole production involves changes in transcription of the hemA gene, which codes for one of two isoenzymes catalyzing 5-aminolevulinic acid synthesis. Regulation of hemA transcription from its two promoters is mediated by the DNA binding proteins FnrL and PrrA. The two PrrA binding sites, binding sites I and II, which are located upstream of the more-5′ hemA promoter (P1), are equally important to transcription under aerobic conditions, while binding site II is more important under anaerobic conditions. By using phosphoprotein affinity chromatography and immunoblot analyses, we showed that the phosphorylated PrrA levels in the cell increase with decreasing oxygen tensions. Then, using both in vivo and in vitro methods, we demonstrated that the relative affinities of phosphorylated and unphosphorylated PrrA for the two binding sites differ and that phosphorylated PrrA has greater affinity for site II. We also showed that PrrA regulation is directed toward the P1 promoter. We propose that the PrrA component of anaerobic induction of P1 transcription is attributable to higher affinity of phosphorylated PrrA than of unphosphorylated PrrA for binding site II. Anaerobic activation of the more-3′ hemA promoter (P2) is thought to involve FnrL binding to an FNR consensuslike sequence located upstream of the P2 promoter, but the contribution of FnrL to P1 induction may be indirect since the P1 transcription start is within the putative FnrL binding site. We present evidence suggesting that the indirect action of FnrL works through PrrA and discuss possible mechanisms.

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Eraso, Jesus M., and Samuel Kaplan. "Half-Site DNA Sequence and Spacing Length Contributions to PrrA Binding to PrrA Site 2 of RSP3361 in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 191, no. 13 (May 1, 2009): 4353–64. http://dx.doi.org/10.1128/jb.00244-09.

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ABSTRACT The consensus DNA binding sequence for PrrA, a global regulator in Rhodobacter sphaeroides 2.4.1, is poorly defined. We have performed mutational analysis of PrrA site 2, of the RSP3361 gene, to which PrrA binds in vitro (J. M. Eraso and S. Kaplan, J. Bacteriol. 191:4341-4352, 2009), to further define the consensus sequence for DNA binding. Two half-sites of equal length, containing 6 nucleotides each, were required for PrrA binding to this DNA sequence. Systematic nucleotide substitutions in both inverted half-sites led to a decrease in binding affinity of phosphorylated PrrA in vitro, the level of which was dependent on the substitution. The reduced binding affinities were confirmed by competition experiments and led to proportional decreases in the expression of lacZ transcriptional fusions to the RSP3361 gene in vivo. The 5-nucleotide spacer region between the half-sites was found to be optimal for PrrA binding to the wild-type half-sites, as shown by decreased PrrA DNA binding affinities to synthetic DNA sequences without spacer regions or with spacer regions ranging from 1 to 10 nucleotides. The synthetic spacer region alleles also showed decreased gene expression in vivo when analyzed using lacZ transcriptional fusions. We have studied three additional DNA sequences to which PrrA binds in vitro. They are located in the regulatory regions of genes positively regulated by PrrA and contain spacer regions with 5 or 8 nucleotides. We demonstrate that PrrA can bind in vitro to DNA sequences with different lengths in the spacer regions between the half-sites.

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Bruscella, Patrice, Jesus M. Eraso, Jung Hyeob Roh, and Samuel Kaplan. "The Use of Chromatin Immunoprecipitation to Define PpsR Binding Activity in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 190, no. 20 (August 8, 2008): 6817–28. http://dx.doi.org/10.1128/jb.00719-08.

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ABSTRACT The expression of genes involved in photosystem development in Rhodobacter sphaeroides is dependent upon three major regulatory networks: FnrL, the PrrBA (RegBA) two-component system, and the transcriptional repressor/antirepressor PpsR/AppA. Of the three regulators, PpsR appears to have the narrowest range of physiological effects, which are limited to effects on the structural and pigment biosynthetic activities involved in photosynthetic membrane function. Although a PrrA− mutant is unable to grow under photosynthetic conditions, when a ppsR mutation was present, photosynthetic growth occurred. An examination of the double mutant under anaerobic-dark-dimethyl sulfoxide conditions using microarray analysis revealed the existence of an “extended” PpsR regulon and new physiological roles. To characterize the PpsR regulon and to better ascertain the significance of degeneracy within the PpsR binding sequence in vivo, we adapted the chromatin immunoprecipitation technique to R. sphaeroides. We demonstrated that in vivo there was direct and significant binding by PpsR to newly identified genes involved in microaerobic respiration and periplasmic stress resistance, as well as to photosynthesis genes. The new members of the PpsR regulon are located outside the photosynthesis gene cluster and have degenerate PpsR binding sequences. The possible interaction under physiologic conditions with degenerate binding sequences in the presence of other biologically relevant molecules is discussed with respect to its importance in physiological processes and to the existence of complex phenotypes associated with regulatory mutants. This study further defines the DNA structure necessary for PpsR binding in situ.

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Cardona, Silvia T., Carmen L. Mueller, and Miguel A. Valvano. "Identification of Essential Operons with a Rhamnose-Inducible Promoter in Burkholderia cenocepacia." Applied and Environmental Microbiology 72, no. 4 (April 2006): 2547–55. http://dx.doi.org/10.1128/aem.72.4.2547-2555.2006.

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ABSTRACT Scanning of bacterial genomes to identify essential genes is of biological interest, for understanding the basic functions required for life, and of practical interest, for the identification of novel targets for new antimicrobial therapies. In particular, the lack of efficacious antimicrobial treatments for infections caused by the Burkholderia cepacia complex is causing high morbidity and mortality of cystic fibrosis patients and of patients with nosocomial infections. Here, we present a method based on delivery of the tightly regulated rhamnose-inducible promoter PrhaB for identifying essential genes and operons in Burkholderia cenocepacia. We demonstrate that different levels of gene expression can be achieved by using two vectors that deliver PrhaB at two different distances from the site of insertion. One of these vectors places PrhaB at the site of transposon insertion, while the other incorporates the enhanced green fluorescent protein gene (e-gfp) downstream from PrhaB . This system allows us to identify essential genes and operons in B. cenocepacia and provides a new tool for systematically identifying and functionally characterizing essential genes at the genomic level.

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26

Eraso, Jesus M., and Samuel Kaplan. "Regulation of Gene Expression by PrrA in Rhodobacter sphaeroides 2.4.1: Role of Polyamines and DNA Topology." Journal of Bacteriology 191, no. 13 (May 1, 2009): 4341–52. http://dx.doi.org/10.1128/jb.00243-09.

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ABSTRACT In the present study, we show in vitro binding of PrrA, a global regulator in Rhodobacter sphaeroides 2.4.1, to the PrrA site 2, within the RSP3361 locus. Specific binding, as shown by competition experiments, requires the phosphorylation of PrrA. The binding affinity of PrrA for site 2 was found to increase 4- to 10-fold when spermidine was added to the binding reaction. The presence of extracellular concentrations of spermidine in growing cultures of R. sphaeroides gave rise to a twofold increase in the expression of the photosynthesis genes pucB and pufB, as well as the RSP3361 gene, under aerobic growth conditions, as shown by the use of lacZ transcriptional fusions, and led to the production of light-harvesting spectral complexes. In addition, we show that negative supercoiling positively regulates the expression of the RSP3361 gene, as well as pucB. We show the importance of supercoiling through an evaluation of the regulation of gene expression in situ by supercoiling, in the case of the former gene, as well as using the DNA gyrase inhibitor novobiocin. We propose that polyamines and DNA supercoiling act synergistically to regulate expression of the RSP3361 gene, partly by affecting the affinity of PrrA binding to the PrrA site 2 within the RSP3361 gene.

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Gibson, Janet L., James M. Dubbs, and F. Robert Tabita. "Differential Expression of the CO2 Fixation Operons of Rhodobacter sphaeroides by the Prr/Reg Two-Component System during Chemoautotrophic Growth." Journal of Bacteriology 184, no. 23 (December 1, 2002): 6654–64. http://dx.doi.org/10.1128/jb.184.23.6654-6664.2002.

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ABSTRACT In Rhodobacter sphaeroides, the two cbb operons encoding duplicated Calvin-Benson Bassham (CBB) CO2 fixation reductive pentose phosphate cycle structural genes are differentially controlled. In attempts to define the molecular basis for the differential regulation, the effects of mutations in genes encoding a subunit of Cbb3 cytochrome oxidase, ccoP, and a global response regulator, prrA (regA), were characterized with respect to CO2 fixation (cbb) gene expression by using translational lac fusions to the R. sphaeroides cbb I and cbbII promoters. Inactivation of the ccoP gene resulted in derepression of both promoters during chemoheterotophic growth, where cbb expression is normally repressed; expression was also enhanced over normal levels during phototrophic growth. The prrA mutation effected reduced expression of cbbI and cbbII promoters during chemoheterotrophic growth, whereas intermediate levels of expression were observed in a double ccoP prrA mutant. PrrA and ccoP1 prrA strains cannot grow phototrophically, so it is impossible to examine cbb expression in these backgrounds under this growth mode. In this study, however, we found that PrrA mutants of R. sphaeroides were capable of chemoautotrophic growth, allowing, for the first time, an opportunity to directly examine the requirement of PrrA for cbb gene expression in vivo under growth conditions where the CBB cycle and CO2 fixation are required. Expression from the cbbII promoter was severely reduced in the PrrA mutants during chemoautotrophic growth, whereas cbbI expression was either unaffected or enhanced. Mutations in ccoQ had no effect on expression from either promoter. These observations suggest that the Prr signal transduction pathway is not always directly linked to Cbb3 cytochrome oxidase activity, at least with respect to cbb gene expression. In addition, lac fusions containing various lengths of the cbbI promoter demonstrated distinct sequences involved in positive regulation during photoautotrophic versus chemoautotrophic growth, suggesting that different regulatory proteins may be involved. In Rhodobacter capsulatus, ribulose 1,5-bisphosphate carboxylase-oxygenase (RubisCO) expression was not affected by cco mutations during photoheterotrophic growth, suggesting that differences exist in signal transduction pathways regulating cbb genes in the related organisms.

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Massart, Catherine, Rémy Sapin, Jacqueline Gibassier, Arnaud Agin, and Michèle d'Herbomez. "Intermethod Variability in TSH-Receptor Antibody Measurement: Implication for the Diagnosis of Graves Disease and for the Follow-Up of Graves Ophthalmopathy." Clinical Chemistry 55, no. 1 (January 1, 2009): 183–86. http://dx.doi.org/10.1373/clinchem.2008.115162.

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Abstract Background: We compared the analytical and clinical performance of 3 porcine thyroid receptor antibody (TRAb) methods (1 second- and 2 new third-generation systems) with the conventional TRAb assay based on the human recombinant TSH receptor (hTRAK). Patients and Methods: We obtained sera from 86 patients with untreated Graves disease (GD) and 71 healthy controls. We measured TRAb concentrations by radioreceptor assay using the hTRAK (Brahms) or the porcine TSH receptor (pRRA) from Beckman-Coulter, by electrochemiluminescence immunoassay (ECLIA) with the Elecsys/Cobas (Roche), and by ELISA using the Medizym TRAb clone (Medipan). Results: Between-run assay imprecision was ≤10% and ≤7.6% for hTRAK and ECLIA, but reached 14% and 14.9% for ELISA and pRRA, respectively. Maximal specificity and sensitivity close to 100% were obtained for hTRAK, ECLIA, and ELISA. pRRA failed to detect positive TRAbs in 5 GD patients. Although calibrated against the same reference standard 90/672, the assays displayed a high intermethod variability. The results were significantly higher by ECLIA and lower by ELISA and pRRA compared with hTRAK. Patients with ophthalmopathy had higher TRAb results by ELISA and pRRA than those without eye disease. Conclusions: Second- and third-generation TRAb assays had similar diagnostic sensitivities in the diagnostic evaluation of GD. Despite the use of the same reference standard for calibration, high intermethod variability in TRAb assay results was seen in untreated GD patients. Assay harmonization is necessary for correct interpretation in the follow-up of Graves ophthalmopathy.

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29

Mikhaljuk, A. N., L. A. Tanana, and O. A. Epishko. "INFLUENCE OF PROLACTIN (PRL) AND BETA-LACTOGLOBULIN (BLG) GENES ON INDICATORS OF DAIRY PERFORMANCE IN COWS OF THE BELARUSIAN BLACK-AND-WHITE BREED." Transactions of the educational establishment “Vitebsk the Order of “the Badge of Honor” State Academy of Veterinary Medicine 57, no. 1 (2021): 99–103. http://dx.doi.org/10.52368/2078-0109-2021-57-1-99-103.

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The results of the studies showed that by the prolactin gene (PRL), the highest yield was found in the first-calf heifers with the PRLBB genotype by 4.7% -10.5% as compared to herd-mates of other genotypes; and in cows of the second and third lactations – with the PRLAB genotype – by 2.6-10.6%. In terms of milk fat, animals with the PRLAB genotype had a higher rate than animals with the PRLAA and PRLBB genotypes by 0.04-0.17 pp, with the second and especially third lactation animals having the most noticeable changes. By the beta-lactoglobulin (BLG) gene, animals with the BLGAA genotype had a higher yield rate for 305 days of lactation in the first-calf heifers; in cows of the second lactation – animals with the BLGAB genotype, and in cows of the third lactation – with the BLGBB genotype. By the content of butterfat and protein in milk, on the contrary,the highest rates in the first calf heifers had animals with the PRLBB genotype; in the second-lactation cows – PRLAB, and in the third-lactation cows – with the PRLAA genotype.

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30

Craith, Delores Nic. "Preab sa Cheol: Rogha ceoil na bliana." Comhar 47, no. 1 (1988): 43. http://dx.doi.org/10.2307/20556427.

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31

Mao, Linyong, Chris Mackenzie, Jung H. Roh, Jesus M. Eraso, Samuel Kaplan, and Haluk Resat. "Combining microarray and genomic data to predict DNA binding motifs." Microbiology 151, no. 10 (October 1, 2005): 3197–213. http://dx.doi.org/10.1099/mic.0.28167-0.

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The ability to detect regulatory elements within genome sequences is important in understanding how gene expression is controlled in biological systems. In this work, microarray data analysis is combined with genome sequence analysis to predict DNA sequences in the photosynthetic bacterium Rhodobacter sphaeroides that bind the regulators PrrA, PpsR and FnrL. These predictions were made by using hierarchical clustering to detect genes that share similar expression patterns. The DNA sequences upstream of these genes were then searched for possible transcription factor recognition motifs that may be involved in their co-regulation. The approach used promises to be widely applicable for the prediction of cis-acting DNA binding elements. Using this method the authors were independently able to detect and extend the previously described consensus sequences that have been suggested to bind FnrL and PpsR. In addition, sequences that may be recognized by the global regulator PrrA were predicted. The results support the earlier suggestions that the DNA binding sequence of PrrA may have a variable-sized gap between its conserved block elements. Using the predicted DNA binding sequences, a whole-genome-scale analysis was performed to determine the relative importance of the interplay between the three regulators PpsR, FnrL and PrrA. Results of this analysis showed that, compared to the regulation by PpsR and FnrL, a much larger number of genes are candidates to be regulated by PrrA. The study demonstrates by example that integration of multiple data types can be a powerful approach for inferring transcriptional regulatory patterns in microbial systems, and it allowed the detection of photosynthesis-related regulatory patterns in R. sphaeroides.

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Son, Myung-Hwa, Min-Ju Kim, and Sang-Joon Lee. "The Role of NifA and PrrA on the Expression of nif Gene in Rhodobacter sphaeroides." Journal of Environmental Science International 21, no. 9 (September 30, 2012): 1139–47. http://dx.doi.org/10.5322/jes.2012.21.9.1139.

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Haldimann, Andreas, Larry L. Daniels, and Barry L. Wanner. "Use of New Methods for Construction of Tightly Regulated Arabinose and Rhamnose Promoter Fusions in Studies of theEscherichia coli Phosphate Regulon." Journal of Bacteriology 180, no. 5 (March 1, 1998): 1277–86. http://dx.doi.org/10.1128/jb.180.5.1277-1286.1998.

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ABSTRACT Escherichia coli genes regulated by environmental inorganic phosphate (Pi) levels form the phosphate (Pho) regulon. This regulation requires seven proteins, whose synthesis is under autogenous control, including response regulator PhoB, its partner, histidine sensor kinase PhoR, all four components of the Pi-specific transport (Pst) system (PstA, PstB, PstC, and PstS), and a protein of unknown function called PhoU. Here we examined the effects of uncoupling PhoB synthesis and PhoR synthesis from their normal controls by placing each under the tight control of the arabinose-regulated ParaB promoter or the rhamnose-regulated PrhaB promoter. To do this, we made allele replacement plasmids that may be generally useful for construction of ParaB orPrhaB fusions and for recombination of them onto the E. coli chromosome at the araCBAD orrhaRSBAD locus, respectively. Using strains carrying such single-copy fusions, we showed that a PrhaB fusion is more tightly regulated than a ParaB fusion in that a PrhaB-phoR + fusion but not a ParaB-phoR + fusion shows a null phenotype in the absence of its specific inducer. Yet in the absence of induction, bothParaB-phoB + andPrhaB-phoB + fusions exhibit a null phenotype. These data indicate that less PhoR than PhoB is required for transcriptional activation of the Pho regulon, which is consistent with their respective modes of action. We also used these fusions to study PhoU. Previously, we had constructed strains with precise ΔphoU mutations. However, we unexpectedly found that such ΔphoU mutants have a severe growth defect (P. M. Steed and B. L. Wanner, J. Bacteriol. 175:6797–6809, 1993). They also readily give rise to compensatory mutants with lesions inphoB, phoR, or a pst gene, making their study particularly difficult. Here we found that, by usingParaB-phoB +,PrhaB-phoB +, orPrhaB-phoR + fusions, we were able to overcome the extremely deleterious growth defect of a Pst+ ΔphoU mutant. The growth defect is apparently a consequence of high-level Pst synthesis resulting from autogenous control of PhoB and PhoR synthesis in the absence of PhoU.

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Errasti, Jose M., Héctor Rifá, and Vlcenç Quera. "Program for Recording and Analyzing Behavior (PRAB)." Psychological Reports 84, no. 1 (February 1999): 191–92. http://dx.doi.org/10.2466/pr0.1999.84.1.191.

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A computer program for recording behavioral data that requires temporal continuity in one or two subjects is presented It runs on compatible PC and provides several behavioral measures for the recorded behaviors such as frequencies, percentages, durations, and sequences. The program can also save data files in both ASCII and SDIS formats for more complex analysis through the SPSS or GSEQ statistical programs.

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35

Song, Renfang, Adam Janssen, Yuwen Li, Samir El-Dahr, and Ihor V. Yosypiv. "Prorenin receptor controls renal branching morphogenesis via Wnt/β-catenin signaling." American Journal of Physiology-Renal Physiology 312, no. 3 (March 1, 2017): F407—F417. http://dx.doi.org/10.1152/ajprenal.00563.2016.

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The prorenin receptor (PRR) is a receptor for renin and prorenin, and an accessory subunit of the vacuolar proton pump H+-ATPase. Renal branching morphogenesis, defined as growth and branching of the ureteric bud (UB), is essential for mammalian kidney development. Previously, we demonstrated that conditional ablation of the PRR in the UB in PRRUB−/− mice causes severe defects in UB branching, resulting in marked kidney hypoplasia at birth. Here, we investigated the UB transcriptome using whole genome-based analysis of gene expression in UB cells, FACS-isolated from PRRUB−/−, and control kidneys at birth (P0) to determine the primary role of the PRR in terminal differentiation and growth of UB-derived collecting ducts. Three genes with expression in UB cells that previously shown to regulate UB branching morphogenesis, including Wnt9b, β-catenin, and Fgfr2, were upregulated, whereas the expression of Wnt11, Bmp7, Etv4, and Gfrα1 was downregulated. We next demonstrated that infection of immortalized UB cells with shPRR in vitro or deletion of the UB PRR in double-transgenic PRRUB−/−/ BatGal+ mice, a reporter strain for β-catenin transcriptional activity, in vivo increases β-catenin activity in the UB epithelia. In addition to UB morphogenetic genes, the functional groups of differentially expressed genes within the downregulated gene set included genes involved in molecular transport, metabolic disease, amino acid metabolism, and energy production. Together, these data demonstrate that UB PRR performs essential functions during UB branching and collecting duct morphogenesis via control of a hierarchy of genes that control UB branching and terminal differentiation of the collecting duct cells.

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Romagnoli, Simona, Helen L. Packer, and Judith P. Armitage. "Tactic Responses to Oxygen in the Phototrophic Bacterium Rhodobacter sphaeroides WS8N." Journal of Bacteriology 184, no. 20 (October 15, 2002): 5590–98. http://dx.doi.org/10.1128/jb.184.20.5590-5598.2002.

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ABSTRACT The temporal and spatial behavior of a number of mutants of the photosynthetic, facultative anaerobe Rhodobacter sphaeroides to both step changes and to gradients of oxygen was analyzed. Wild-type cells, grown under a range of conditions, showed microaerophilic behavior, accumulating in a 1.3-mm band about 1.3 mm from the meniscus of capillaries. Evidence suggests this is the result of two signaling pathways. The strength of any response depended on the growth and incubation conditions. Deletion of either the complete chemosensory operons 1 and 2 plus the response regulator genes cheY4 and cheY5 or cheA2 alone led to the loss of all aerotactic responses, although the cells still swam normally. The Prr system of R. sphaeroides responds to electron flow through the alternative high-affinity cytochrome oxidase, cbb 3, controlling expression of a wide range of metabolic pathways. Mutants with deletions of either the complete Prr operon or the histidine kinase, PrrB, accumulated up to the meniscus but still formed a thick band 1.3 mm from the aerobic interface. This indicates that the negative aerotactic response to high oxygen levels depends on PrrB, but the mutant cells still retain the positive response. Tethered PrrB− cells also showed no response to a step-down in oxygen concentration, although those with deletions of the whole operon showed some response. In gradients of oxygen where the concentration was reduced at 0.4 μM/s, tethered wild-type cells showed two different phases of response, with an increase in stopping frequency when the oxygen concentration fell from 80 to 50% dissolved oxygen and a decrease in stopping at 50 to 20% dissolved oxygen, with cells returning to their normal stopping frequency in 0% oxygen. PrrB and CheA2 mutants showed no response, while PrrCBA mutants still showed some response.

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Aleynick, Mark, Paul Peng, Linda Hammerich, Ranjan Upadhyay, Netonia Marshall, Judith Agudo, Michael Jay Yellin, et al. "Natural pattern-recognition-receptor agonists as adjuvants for in situ vaccination lymphoma immunotherapy." Journal of Clinical Oncology 36, no. 5_suppl (February 10, 2018): 123. http://dx.doi.org/10.1200/jco.2018.36.5_suppl.123.

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123 Background: In patients with low-grade lymphoma, in situ vaccination has yielded both partial and complete remissions in clinical trials. Though clinical responses have been observed with multiple pattern recognition receptor agonists (PRRa), the optimal immune stimulant is unknown. We hypothesize that natural PRRa, such as the attenuated pathogens or subunits found in common prophylactic vaccines, could target multiple PRR in a physiologically relevant context and lead to a more robust activation of dendritic cells (DCs) versus synthetic PRRa. Methods: 20 vaccines, including BCG, Typhim Vi, MMR-II, etc. were screened in vitro, where DC phenotype and function were evaluated by flow cytometry. Flt3L-mobilized DC ability to phagocytose, process, present, and cross-present soluble protein or tumor derived antigen, were assessed using CRISPR gene-edited, β2m(-/-) GFP-lymphoma cells and a novel GFP-specific (‘JEDI’) CD8 T cell system. Vaccine mechanism of immune activation was elucidated using a library of PRR-null macrophage cell lines. Potent vaccines were also evaluated in vivo in a Flt3L-primed in situ vaccination using the A20 murine lymphoma model. Results: Several vaccines induced robust DC activation and several showed significant increases in subsequent T cell activation, proliferation, and tumor killing, suggesting increased antigen processing and cross-presentation by DCs. Some vaccines, either as single agents or in combination, were significantly more effective than synthetic PRRa in activating DCs and inducing a T cell response. In vivo, vaccine combination therapies induced tumor regression in a majority of animals, suggesting synergistic immune activation. Conclusions: This data suggests prophylactic vaccines are effective clinical-grade DC activators and can be repurposed for use in the in situ vaccination maneuver, with immediate translation into the clinic. Additionally, by extensive in vitro evaluation in parallel with in vivo studies, this work aims to identify a predictive in vitro molecular immune signature that correlates closely with adjuvant efficacy in vivo.

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Jäger, Andreas, Stephan Braatsch, Kerstin Haberzettl, Sebastian Metz, Lisa Osterloh, Yuchen Han, and Gabriele Klug. "The AppA and PpsR Proteins from Rhodobacter sphaeroides Can Establish a Redox-Dependent Signal Chain but Fail To Transmit Blue-Light Signals in Other Bacteria." Journal of Bacteriology 189, no. 6 (January 5, 2007): 2274–82. http://dx.doi.org/10.1128/jb.01699-06.

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ABSTRACT The AppA protein of Rhodobacter sphaeroides has the unique ability to sense and transmit redox and light signals. In response to decreasing oxygen tension, AppA antagonizes the transcriptional regulator PpsR, which represses the expression of photosynthesis genes, including the puc operon. This mechanism, which is based on direct protein-protein interaction, is prevented by blue-light absorption of the BLUF domain located in the N-terminal part of AppA. In order to test whether AppA and PpsR are sufficient to transmit redox and light signals, we expressed these proteins in three different bacterial species and monitored oxygen- and blue-light-dependent puc expression either directly or by using a luciferase-based reporter construct. The AppA/PpsR system could mediate redox-dependent gene expression in the alphaproteobacteria Rhodobacter capsulatus and Paracoccus denitrificans but not in the gammaproteobacterium Escherichia coli. Analysis of a prrA mutant strain of R. sphaeroides strongly suggests that light-dependent gene expression requires a balanced interplay of the AppA/PpsR system with the PrrA response regulator. Therefore, the AppA/PpsR system was unable to establish light signaling in other bacteria. Based on our data, we present a model for the interdependence of AppA/PpsR signaling and the PrrA transcriptional activator.

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Oh, Jeong-Il, In-Jeong Ko, and Samuel Kaplan. "Reconstitution of theRhodobacter sphaeroidescbb3-PrrBA Signal Transduction Pathway in Vitro†." Biochemistry 43, no. 24 (June 2004): 7915–23. http://dx.doi.org/10.1021/bi0496440.

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Ewann, Fanny, Camille Locht, and Philip Supply. "Intracellular autoregulation of the Mycobacterium tuberculosis PrrA response regulator." Microbiology 150, no. 1 (January 1, 2004): 241–46. http://dx.doi.org/10.1099/mic.0.26516-0.

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Lata, Sneh, and Gajendra Raghava. "PRRDB: A comprehensive database of Pattern-Recognition Receptors and their ligands." BMC Genomics 9, no. 1 (2008): 180. http://dx.doi.org/10.1186/1471-2164-9-180.

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Zeilstra-Ryalls, Jill H., and Kathryn L. Schornberg. "Analysis of hemF Gene Function and Expression in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 188, no. 2 (January 15, 2006): 801–4. http://dx.doi.org/10.1128/jb.188.2.801-804.2006.

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ABSTRACT The hemF gene of Rhodobacter sphaeroides 2.4.1 is predicted to code for an oxygen-dependent coproporphyrinogen III oxidase. We found that a HemF− mutant strain is unable to grow under aerobic conditions. We also determined that hemF expression is controlled by oxygen, which is mediated, at least in part, by the response regulatory protein PrrA.

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Laguri, Cédric, Rachelle A. Stenzel, Timothy J. Donohue, Mary K. Phillips-Jones, and Michael P. Williamson. "Activation of the Global Gene Regulator PrrA (RegA) fromRhodobacter sphaeroides†." Biochemistry 45, no. 25 (June 2006): 7872–81. http://dx.doi.org/10.1021/bi060683g.

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Smirnova, T. N. "A model prorab machine and solution of problems with very sparse quantities." Journal of Soviet Mathematics 28, no. 3 (February 1985): 409–39. http://dx.doi.org/10.1007/bf02104313.

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Guimarães, Deborah de Almeida Bauer, Danielle dos Santos Bonfim De Castro, Felipe Leite de Oliveira, Eduardo Matos Nogueira, Marco Antônio Mota da Silva, and Anderson Junger Teodoro. "Pitaya Extracts Induce Growth Inhibition and Proapoptotic Effects on Human Cell Lines of Breast Cancer via Downregulation of Estrogen Receptor Gene Expression." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/7865073.

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Breast cancer is one of the most prevalent cancers in the world and is also the leading cause of cancer death in women. The use of bioactive compounds of functional foods contributes to reduce the risk of chronic diseases, such as cancer and vascular disorders. In this study, we evaluated the antioxidant potential and the influence of pitaya extract (PE) on cell viability, colony formation, cell cycle, apoptosis, and expression of BRCA1, BRCA2, PRAB, and Erα in breast cancer cell lines (MCF-7 and MDA-MB-435). PE showed high antioxidant activity and high values of anthocyanins (74.65 ± 2.18). We observed a selective decrease in cell proliferation caused by PE in MCF-7 (ER+) cell line. Cell cycle analysis revealed that PE induced an increase in G0/G1 phase followed by a decrease in G2/M phase. Also, PE induced apoptosis in MCF-7 (ER+) cell line and suppressed BRCA1, BRCA2, PRAB, and Erα gene expression. Finally, we also demonstrate that no effect was observed with MDA-MB-435 cells (ER−) after PE treatment. Taken together, the present study suggests that pitaya may have a protective effect against breast cancer.

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Oh, Jeong-Il, Jesus M. Eraso, and Samuel Kaplan. "Interacting Regulatory Circuits Involved in Orderly Control of Photosynthesis Gene Expression in Rhodobacter sphaeroides 2.4.1." Journal of Bacteriology 182, no. 11 (June 1, 2000): 3081–87. http://dx.doi.org/10.1128/jb.182.11.3081-3087.2000.

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ABSTRACT FnrL, the homolog of the global anaerobic regulator Fnr, is required for the induction of the photosynthetic apparatus inRhodobacter sphaeroides 2.4.1. Thus, the precise role of FnrL in photosynthesis (PS) gene expression and its interaction(s) with other regulators of PS gene expression are of considerable importance to our understanding of the regulatory circuitry governing spectral complex formation. Using a CcoP and FnrL double mutant strain, we obtained results which suggested that FnrL is not involved in the transduction of the inhibitory signal, by which PS gene expression is “silenced,” emanating from thecbb 3 oxidase encoded by the ccoNOQPoperon under aerobic conditions. The dominant effect of theccoP mutation in the FnrL mutant strain with respect to spectral complex formation under aerobic conditions and restoration of a PS-positive phenotype suggested that inactivation of thecbb 3 oxidase to some extent bypasses the requirement for FnrL in the formation of spectral complexes. Additional analyses revealed that anaerobic induction of thebchE, hemN, and hemZ genes, which are involved in the tetrapyrrole biosynthetic pathways, requires FnrL. Thus, FnrL appears to be involved at multiple loci involved in the regulation of PS gene expression. Additionally, bchE was also shown to be regulated by the PrrBA two-component system, in conjunction with hemN and hemZ. These and other results to be discussed permit us to more accurately describe the role of FnrL as well as the interactions between the FnrL, PrrBA, and other regulatory circuits in the regulation of PS gene expression.

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47

Merighi, Massimo, Amanda Carroll-Portillo, Alecia N. Septer, Aditi Bhatiya, and John S. Gunn. "Role of Salmonella enterica Serovar Typhimurium Two-Component System PreA/PreB in Modulating PmrA-Regulated Gene Transcription." Journal of Bacteriology 188, no. 1 (January 1, 2006): 141–49. http://dx.doi.org/10.1128/jb.188.1.141-149.2006.

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ABSTRACT The PmrA/PmrB two-component system encoded by the pmrCAB operon regulates the modification of Salmonella enterica serovar Typhimurium lipopolysaccharide leading to polymyxin B resistance. PmrA and PhoP are the only known activators of pmrCAB. A transposon mutagenesis screen for additional regulators of a pmrC::MudJ fusion led to the identification of a two-component system, termed PreA/PreB (pmrCAB regulators A and B), that controls the transcription of the pmrCAB operon in response to unknown signals. The initial observations indicated that insertions in, or a deletion of, the preB sensor, but not the preA response regulator, caused upregulation of pmrCAB. Interestingly, the expression of pmrCAB was not upregulated in a preAB mutant grown in LB broth, implicating PreA in the increased expression of pmrCAB in the preB strain. This was confirmed by overexpression of preA + in preAB or preB backgrounds, which resulted in significant upregulation or further upregulation of pmrCAB. No such effect was observed in any tested preB + backgrounds. Additionally, an ectopic construct expressing a preA[D51A] allele also failed to upregulate pmrC in any of the pre backgrounds tested, which implies that there is a need for phosphorylation in the activation of the target genes. The observed upregulation of pmrCAB occurred independently of the response regulators PmrA and PhoP. Although a preB mutation led to increased transcription of pmrCAB, this did not result in a measurable effect on polymyxin B resistance. Our genetic data support a model of regulation whereby, in response to unknown signals, the PreB sensor activates PreA, which in turn indirectly upregulates pmrCAB transcription.

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48

KORNACKI, JEFFREY L., JOSHUA B. GURTLER, ZHINONG YAN, and CHAD M. COOPER. "Evaluation of Several Modifications of an Ecometric Technique for Assessment of Media Performance." Journal of Food Protection 66, no. 9 (September 1, 2003): 1727–32. http://dx.doi.org/10.4315/0362-028x-66.9.1727.

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Recovery of Listeria monocytogenes 101M, Jonesia denitrificans, salmonellae, and Pediococcus sp. NRRL B-2354 across nine media was evaluated with three modified versions of an ecometric method. Two approaches involved the use of broth cultures (108 to 109 CFU/ml) of individual strains and either large (10-μl) or small (1-μl) presterilized plastic loops. The third approach involved precultured slants and the inoculation of media with presterilized plastic inoculating needles (104 CFU per needle). Absolute growth indices (AGIs) were compared. No significant differences (P < 0.05) between methods were found when tryptic soy agar supplemented with 0.6% yeast extract (TSAYE) was used for the recovery of L. monocytogenes, J. denitrificans, Pediococcus sp. NRRL B-2354, and Salmonella spp. However, the small loop–broth technique recovered significantly fewer Salmonella enterica Typhimurium DT104 and Salmonella Senftenberg 775W cells than the other two techniques did. The performance of each individual bacterial strain on each of nine media was assayed. The recovery of L. monocytogenes was excellent (AGI > 4.8) with TSAYE, PALCAM, modified Oxford medium (MOX), and Baird-Parker agar and slight with modified PRAB (AGI = 0.4) and deMan Rogosa Sharpe (MRS) agar (<0.1), and the organism was not recovered with the remaining media (modified lysine iron agar [MLIA], xylose lysine desoxycholate [XLD] agar, and xylose lysine tergitol 4 [XLT4] agar). The recovery of J. denitrificans with TSAYE and MOX was excellent, significantly better than that achieved with PALCAM (AGI = 3.0), but the organism was not recovered with Baird-Parker agar or with the other media tested. The recovery of Pediococcus sp. NRRL B-2354 was excellent with TSAYE and modified PRAB medium > Baird-Parker agar > acidified MRS agar, but the organism was not recovered with any of the other media tested. The best recovery of S. enterica Typhimurium DT104 was achieved with TSAYE > MLIA ≥ XLD agar ≥ XLT4 agar > Baird-Parker > PALCAM, MOX, acidified MRS agar, modified PRAB, and MRS agar. The best recovery of Salmonella Senftenberg 775W was achieved with TSAYE, MLIA, and XLD agar > XLT4 agar, but the organism was not recovered with the other media evaluated.

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49

Deepika Patil, Ms, and Mrs Nitika Vats Doohan. "TAB-PRRA: Improved Link Repair Decision Mechanism for Ondemand Routing in MANET." IOSR Journal of Computer Engineering 16, no. 1 (2014): 107–12. http://dx.doi.org/10.9790/0661-1614107112.

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Dhonnchadha, Máire Treasa Ní. "Preab sa Cheol: 'Níl an ceol traidisiúnta imithe go hiomlán as ár gcuid fola'." Comhar 47, no. 3 (1988): 22. http://dx.doi.org/10.2307/20556459.

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Journal articles on the topic 'PrrAB'

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