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1
Szekeres, Ferenc. "Bioinformatics applied to chlorophyll a/b binding proteins in Avena sativa (oat)." Thesis, University of Skövde, Department of Computer Science, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-820.
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The chlorophyll a/b binding (CAB) genes play a very central role in all photosynthetic systems and are for Avena sativa (oat) totally unexplored. This dissertation investigates a large number of EST sequences and this investigation characterises the CAB genes in oat, with help from the evolutionary background of oat and the comparison to a reference organism and similar species.
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Schmidt, Kristin. "Pigmentbindung verschiedener Mitglieder der erweiterten Chlorophyll-a-b-Proteinfamilie und des wasserlöslichen Chlorophyll-Proteins WSCP." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968710921.
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Wang, Hui. "Immunoglobulin binding proteins in ticks." Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:7c09068b-82fb-4434-9e84-4663cbab7795.
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Jones, Gareth. "NMR studies of the DNA-binding domain of B-Myb." Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270703.
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Sarma, Ranjana. "Investigations of nucleotide-dependent electron transfer and substrate binding in nitrogen fixation and chlorophyll biosynthesis." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/sarma/SarmaR1209.pdf.
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The studies presented in this thesis include studies of nucleotide-dependent conformations of the electron donor protein in nitrogenase and dark-operative protochlorophyllide reductase (DPOR) characterized using small-angle x-ray scattering and x-ray diffraction methods. Nitrogen fixation and chlorophyll synthesis are involved in the reduction of high energy bonds under physiological conditions. Both make use of elegant reaction mechanisms made possible by complex enzyme systems which are evolutionarily related. Nitrogenase reduces nitrogen to ammonia and is a two-component metalloenzyme composed of Fe protein and MoFe protein. For nitrogen reduction, the Fe protein and MoFe protein associate and dissociate in a manner concomitant with hydrolysis of at least two MgATP molecules and enables the concomitant transfer of at least one electron from Fe protein to MoFe protein. During chlorophyll biosysnthesis, the rate limiting step is catalyzed by a two-component metalloenzyme called DPOR. The two components of DPOR are BchL and BchNB proteins and these share high level of sequence similarity with the Fe protein and the MoFe protein, respectively. Based on this sequence similarity and biochemical data available, it is proposed that the reaction mechanism is similar to nitrogenase mechanism in which the components of DPOR associate and dissociate in a nucleotide dependent manner, to enable intercomponent electron transfer. Fe protein and BchL present as unique examples of proteins that couple nucleotide dependent conformational change to enable electron transfer for high energy bond reduction. The present studies have been directed at studying the low resolution studies of MgATP-bound wild-type Fe protein and its comparison to the structure of the proposed mimic, i.e, L127 Delta Fe protein. The studies presented show evidence of the MgATP-bound wild-type Fe protein having a conformation very different from the L127 Delta Fe protein. The chapters also include detailed characterization of the structure of BchL in both MgADP bound and nucleotide-free states which offer detailed insights in the structure based mechanism of BchL, with primary focus on identifying key residues involved in componenet docking and in electron transfer. Together, the studies on the Fe protein and BchL have furthered our understanding of mechanism of electron transfer in these complex enzyme systems.
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Taylor, John Philip. "Sub-cellular localisation and function of calcineurin B-like proteins in plant cells." Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268512.
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Price, Gregory A. "Immunogenicity of the Gonococcal Transferrin Binding Proteins." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd_retro/76.
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The gonococcal transferrin binding proteins (Tbps) are two surface-exposed outer membrane proteins, TbpA and TbpB, which together function to remove and internalized iron from human transferrin. Iron is an essential nutrient to the gonococcus, without which it cannot survive. The Tbps have been established as virulence factors, demonstrating their importance in establishing infection. Both TbpA and TbpB are well conserved among gonococcal isolates, and have been considered potential vaccine targets. Vaccine studies with the closely related species Neisseria meningitidis, have demonstrated these proteins to be protective in murine challenge studies. Though the meningococcal Tbps have demonstrated promise, no similar gonococcal vaccine experiments have been conducted prior to the current studies. Here we demonstrate purification of recombinant TbpA and TbpB. These recombinant proteins were utilized to evaluate the human immune response to these proteins during natural infections, and their immunogenicity in murine vaccine studies. Our results demonstrate a paucity of antibodies elicited to these proteins during natural infections in serum and mucosal secretions from infected individuals. From this study we hypothesized the induction of both serum and genital antibodies to these proteins could serve to protect an individual from infection. To begin testing this hypothesis, we immunized mice both intranasally (IN) and subcutaneously (s.c.) with full-length Tbps in conjunction with the B subunit of cholera toxin (Ctb) as an adjuvant. We also performed another vaccine study using domains from both proteins in genetic fusions with Ctb and E. coli heat labile toxin IIb (LtbIIb). Both studies demonstrated that these antigens were immunogenic, as Tbp-specific antibodies were elicited in the serum and vaginal washes of female Balb/C mice. Intranasal immunization however was the only route with which we were able to elicit vaginal Tbp-specific IgA, and IgG, whereas subcutaneous immunization only elicited vaginal IgG. Furthermore, we found the full-length Tbps and the Ctb/LtbIIb chimeras were able to elicit bactericidal antibodies, which were also effective in killing heterologous gonococcal strains. This body of work comprises the first published study using the gonococcal transferrin binding proteins as vaccine antigens, and highlights their potential as vaccine antigens in the development of an efficacious gonococcal vaccine.
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Fernandez, D. S. "Signalling in Trypanosoma b. brucei mediated by GTP-binding proteins and phosphorylation." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598993.
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Antisera raised against the C-terminal decapeptide of Gsα, (RMHLRQYELL or RM), immunodetected polypeptides of 52, 45 and 42 kDa species consistent with identified mammalian species. The specificity of the immunoreactivity was demonstrated by competition with preincubations utilising the decapeptide RM against which the antiserum was raised. Antibodies to Gi and Gq and their respective competing peptides were also utilised. These indicated the presence of a 41 kDa polypeptide cross-reactive with anti-Gi and two polypeptides of 43 and 42 kDa cross-reactive with anti-Gq in trypanosome extracts. GTP binding proteins of T. b. brucei were additionally identified by [α32P]-GTP binding. This method elucidated polypeptides of 65, 52, 45 and 41 kDa as well as low molecular weight polypeptides (less than 30 kDa) typical in size and abundance of members of the ras superfamily. GTP-binding proteins were also labelled by a photoaffinity reaction by UV irradiation in the presence of [α32P]-GTP, identifying polypeptides of 160, 140, 65, 52 and 45 kDa in trypanosomes which co-localised with CS1-immunoreactive species. Cholera toxin catalysed ADP-ribosylations of 52 and 45 kDa polypeptides while pertussis toxin mediated the ADP-ribosylation of 41-43 kDa polypeptides; consistent with observations for mammalian species and the immoreactivity data presented. The role of tyrosine kinase signalling pathways was also studied. By stimulating conditions required for transformation of the bloodstream form to the procyclic, increases in autophosphorylating kinase activity and tyrosine phosphorylation were observed. Phosphorylations on polypeptides of 138, 87, 66, 60 and 46 kDa were found to be alkaline stable, identifying them as possible tyrosine kinases. Phosphoamino acid analysis confirmed phosphorylation of tyrosine of polypeptides of 138, 66 and 46 kDa. The autophosphorylating kinase activity of a 138 kDa polypeptide was found to be 1) stimulated by EGF; 2) shown to be alkaline resistance and; 3) to be phosphorylated on tyrosine which indicate it might be the putative EGF receptor tyrosine kinase of T. brucei while a 98 kDa polypeptide was identified by immunoblotting as a possible insulin receptor kinase.
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Joshi, Jidnyasa [Verfasser], and Claudia [Akademischer Betreuer] Büchel. "Biochemical characterization of Fucoxanthin Chlorophyll a/c binding proteins in the diatom Phaeodactylum tricornutum / Jidnyasa Joshi. Gutachter: Claudia Büchel." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2012. http://d-nb.info/1044772700/34.
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Galloway, Alison. "The RNA binding proteins ZFP36L1 and ZFP36L2 are essential for B lymphocyte development." Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/283950.
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Chen, Hui-Chen. "Role for cyclic adenosine monophosphate (cAMP) response element binding proteins in B lymphocyte development and functional maturation." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1061213266.
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Thesis (Ph. D.)--Ohio State University, 2003.Document formatted into pages. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 Aug. 19.
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Leanna, Candice A. "Loss of IkB[alpha]-mediated regulation correlates with increased oncogenicity of mutant c-Rel proteins." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901255.
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Tibiletti, Tania. "Functional studies on the Light-harvesting-Like (LiL) Proteins in Cyanobacteria and Cryptophytes." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-59801.
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The light-harvesting like (LiL) proteins are a widely spread group of proteins within photosynthetic organisms. They are membrane proteins composed of one to four transmembrane helices and – in homology to the light-harvesting complexes of algae and higher plants – at least one of these transmembrane helices contains the chlorophyll a/b-binding (CAB) domain. Opposite to the light-harvesting antenna complexes, LiL proteins are stress induced and they have been shown to be involved in protection of the photosynthetic apparatus. The work presented in this thesis is focused on understanding the function of one-helical LiL proteins of the cryptophyte algae Guillardia theta and the cyanobacterium Synechocystis sp. PCC 6803. G. theta contains two genes encoding LiL proteins, one is localized in the plastid (hlipP), the other in the nucleomorph (HlipNm). Both genes are expressed in normal growth condition, but they are not induced by high light. Immunostaining indicated that HlipNm is translated, but not light-induced. These proteins therefore seem not to be involved in photoprotective mechanisms of G. theta. In the cyanobacterium Synechocystis sp. PCC 6803 four one-helical LiL proteins were identified, they are called Small CAB-like Proteins (SCPs); a fifth LiL (ScpA) is fused with the ferrochelatase (FC), an enzyme involved in the heme synthesis. Our analysis revealed that SCPs are involved in the de novo assembly/repair cycle of Photosystem II, stabilizing the chlorophyll pigments at their protein scaffold. The in vitro characterization of the recombinant FC showed that ScpA is involved in the product-release of the catalytic domain of the enzyme, thereby regulating substrate availability for chlorophyll- or heme- biosynthesis. Finally, using a transcriptomic and metabolomic approaches, I was able to show that deletion of all SCP genes has profound impact on the cell organization and metabolism. In SCP-depleted cells, production of reactive oxygen species (ROS) is increased, while the amount of Photosystem II per cell volume is decreased, causing a macronutrient-deficient phenotype. Therefore, SCPs are important for stress protection and help to maintain a metabolic equilibrium within the cell.
14
Stokes, Russell Hayden. "Meningococcal transferrin binding proteins A and B form a functional human serum transferrin receptor." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313503.
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Arkbåge, Karin. "Vitamin B₁₂, folate and folate-binding proteins in dairy products : analysis, process retention and bioavailability /." Uppsala : Dept. of Food Science, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a430.pdf.
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Li, Hongzhao. "Regulation of malignant B cell migration by PI(3,4)P2-specific phosphatases and binding proteins." PLOS, 2009. http://hdl.handle.net/1993/30159.
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Cell migration is critical to a wide range of physiological and pathological events and is central to disease progression of B lymphocyte (B cell)-derived leukemia and lymphoma as well as many other types of cancer. It is extensively controlled by phosphoinositide 3-kinase (PI3K), which generates PI(3,4,5)P3 (PIP3) and PI(3,4)P2, lipid messengers that recruit pleckstrin homology (PH)-domain-containing signaling proteins. While PIP3 is known to regulate cell migration, it remains a major unanswered question in the field whether PI(3,4)P2 is also implicated in this cellular function.
A series of investigations here on PI(3,4)P2-specific lipid phosphatases and binding proteins in the context of chemotaxing malignant B cells provide the first insights into a previously unappreciated role of PI(3,4)P2 signaling in cell migration. First, I used physiological regulators of PI(3,4)P2, the inositol polyphosphate 4-phosphatase (INPP4) enzymes, as tool to manipulate PI(3,4)P2 levels to determine the function of this lipid second messenger. PI(3,4)P2 depletion by INPP4A or INPP4B relative to phosphatase-dead mutants indicated an essential role of PI(3,4)P2 in mediating both the speed and directionality of chemotaxis.
Gene silencing of the authenticated PI(3,4)P2-specific binding protein TAPP2 leads to reduced migration speed and directionality, similar to PI(3,4)P2 depletion. The impaired migration is underlain by alterations in chemokine-induced rearrangement of the actin cytoskeleton, loss of migratory polarity and dysregulation of the leading edge activator Rac.
A putative PI(3,4)P2-binding protein, lamellipodin (Lpd), is found to strongly colocalize with PI(3,4)P2 depending on the Lpd PH domain. Lpd knock-down rescue experiments indicated that PI(3,4)P2 controls directionality through Lpd, while Lpd also promotes motility independently of PH domain binding to PI(3,4)P2.
The PI(3,4)P2-binding protein kinase Akt/PKB (also binds to PIP3) is found to play a positive role in the B cell context. Here, PI(3,4)P2 depletion does not inhibit phosphorylation of Akt but seemingly reduces its activity. It is likely that PI(3,4)P2 mediates malignant B cell migration in part through promoting Akt activity.
Taken together, the thesis work establishes the PI(3,4)P2 pathway as a novel branch of the PI3K signaling network controlling cell migration and suggests that PI(3,4)P2 may integrate diverse downstream migratory pathways to impact on cell migration.
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Kashuba, Elena. "Identification of EBNA binding cellular proteins, using yeast two-hybrid system /." Stockholm, 2002. http://diss.kib.ki.se/2003/91-7349-416-X/.
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Richardson, Nathan. "Secondary structure for the apolipoprotein B mRNA editing site : au-binding proteins interact with a stemloop." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313816.
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Hernández-Prieto, Miguel Angel. "The Small Cab-like Proteins in the cyanobacterium Synechocystis sp. PCC 6803." Doctoral thesis, Umeå universitet, Kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-25886.
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The Small Cab-like Proteins (SCPs) in the cyanobacterium Synechocystis sp. PCC 6803 accumulate in cells grown under different stress conditions. Genes coding for SCPs have been found in all sequenced organisms performing oxygenic photosynthesis and even in the genomes of cyanophages. Deletion of multiple scp genes in Synechocystis resulted in mutants with severely impaired growth and altered pigment content. These findings indicate the importance of SCPs in photosynthesis; however, their specific function is not well understood. SCPs share a chlorophyll-binding motif with the plant light harvesting complex, suggesting that they bind chlorophyll. Here I describe my findings, which unambiguously show that SCPs are able to bind chlorophyll in vitro. Although they affect both the stoichiometric ratio of Photosystem I to II and chlorophyll stability, they do not seem to be directly involved in non-photochemical quenching. I was able to reveal the location of the SCPs within the cyanobacterial cell: in stressed cells they attach to Photosystem II in the thylakoid membrane. Furthermore, I revealed the presence of another light-harvesting like (Lil)/SCP protein in Synechocystis sp. PCC 6803. The gene, slr1544, codifying for this newly characterised LilA protein, co-transcribes together with scpD and also appears to bind to Photosystem II during stress.
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Sachdev, Shrikesh. "Autoregulatory feedback control of c-Rel by IkB[alpha] : loss of IkB[alpha]-mediated control over nuclear import and DNA-binding enables oncogenic activation of c-Rel /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901276.
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Song, Bo [Verfasser], Hauke [Akademischer Betreuer] Lilie, Harald [Akademischer Betreuer] Kolmar, and Marcus [Akademischer Betreuer] Fändrich. "Affilin binding proteins selected against a class B GPCR ectodomain / Bo Song. Betreuer: Hauke Lilie ; Harald Kolmar ; Marcus Fändrich." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2012. http://d-nb.info/1025302435/34.
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Adams, Stephanie Caroline Johanna. "Receptor interacting proteins die Rolle der NF-[kappa]B-Aktivatoren bei der Wundheilung der Haut und der epidermalen Differenzierung /." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/992999790/04.
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Wan, Shanshan. "DEK oncoprotein is a novel regulator of NF-kB transactivation and DNA damage-induced apoptosis /." Connect to full text in OhioLINK ETD Center, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1248881814.
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Dissertation (Ph.D.)--University of Toledo, 2009.Typescript. "Submitted as a partial fulfillment of the requirements for the Doctor of Philosophy degree in Biology." Bibliography: leaves 135-146.
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Nygren, Babol Linnéa. "Folate binding protein in bovine milk : occurrence and properties studied with surface plasmon resonance /." Uppsala : Dept. of Food Science, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007102.pdf.
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Wikström, Ingela. "Molecular genetics of B- and T-lymphocyte development /." Umeå : Department of Medical Biosciences, Umeå University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-802.
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Yaciuk, Jane Cherie. "Mechanisms of T cell tolerance to the RNA-binding nuclear autoantigen human La/SS-B." Oklahoma City : [s.n.], 2008.
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Berugoda, Arachchige Danushka M. "Targeting Anti-apoptotic Bcl-2 Proteins with Scyllatoxin-based BH3 Domain Mimetics." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1578306165965544.
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Lu, Bin. "Roles of cellular FLICE-inhibitory protein (c-FLIP) and Pl3K/Akt in Fas (CD95)-induced NF-[kappa]B activation and apoptosis through death effector domains." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4344.
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Thesis (Ph. D.)--West Virginia University, 2005.Title from document title page. Document formatted into pages; contains viii, 95 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 82-95).
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Simon, Glenn C. "Endosomes and mitosis : FIP3-associated vesicle delivery during cytokinesis /." Connect to abstract via ProQuest. Full text is not available online, 2008.
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Gardner, Katherine Lynn. "New insights into the disease mechanisms of Duchenne muscular dystrophy through analyses of the dystrophin, I[kappa]B[beta], and CASK proteins." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1153530409.
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Amer, Ayman Salah-el-deen. "Cytoanalysis of pancreatic B-cells using an avian model, mammalian tissue culture and implications of antisense oligonucleotides transfection /." Huntington, WV : [Marshall University Libraries], 2004. http://www.marshall.edu/etd/descript.asp?ref=474.
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Theses (Ph. D.)--Marshall University, 2004.Title from document title page. Includes abstract. Document formatted into pages: contains xiv, 192 p. including illustrations. Bibliography: p. 157-192.
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Szpryngiel, Scarlett. "Structure and lipid interactions of membrane-associated glycosyltransferases : Cationic patches and anionic lipids regulate biomembrane binding of both GT-A and GT-B enzymes." Doctoral thesis, Stockholms universitet, Institutionen för biokemi och biofysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131084.
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This thesis concerns work on structure and membrane interactions of enzymes involved in lipid synthesis, biomembrane and cell wall regulation and cell defense processes. These proteins, known as glycosyltransferases (GTs), are involved in the transfer of sugar moieties from nucleotide sugars to lipids or chitin polymers. Glycosyltransferases from three types of organisms have been investigated; one is responsible for vital lipid synthesis in Arabidopsis thaliana (atDGD2) and adjusts the lipid content in biomembranes if the plant experiences stressful growth conditions. This enzyme shares many structural features with another GT found in gram-negative bacteria (WaaG). WaaG is however continuously active and involved in synthesis of the protective lipopolysaccharide layer in the cell walls of Escherichia coli. The third type of enzymes investigated here are chitin synthases (ChS) coupled to filamentous growth in the oomycete Saprolegnia monoica. I have investigated two ChS-derived MIT domains that may be involved in membrane interactions within the endosomal pathway. From analysis of the three-dimensional structure and the amino-acid sequence, some important regions of these very large proteins were selected for in vitro studies. By the use of an array of biophysical methods (e.g. Nuclear Magnetic Resonance, Fluorescence and Circular Dichroism spectroscopy) and directed sequence analyses it was possible to shed light on some important details regarding the structure and membrane-interacting properties of the GTs. The importance of basic amino-acid residues and hydrophobic anchoring segments, both generally and for the abovementioned proteins specifically, is discussed. Also, the topology and amino-acid sequence of GT-B enzymes of the GT4 family are analyzed with emphasis on their biomembrane association modes. The results presented herein regarding the structural and lipid-interacting properties of GTs aid in the general understanding of glycosyltransferase activity. Since GTs are involved in a high number of biochemical processes in vivo it is of outmost importance to understand the underlying processes responsible for their activity, structure and interaction events. The results are likely to be useful for many applications and future experimental design within life sciences and biomedicine.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.
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Hallatschek, Werner. "Die Regulation des humanen Lipopolysaccharid bindenden Proteins (hLBP)." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2005. http://dx.doi.org/10.18452/15202.
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Das Lipopolysaccharid Bindende Protein (LBP) ist ein überwiegend in der Leber synthetisiertes Akutphaseprotein. Es bindet den Zellwandbestandteil Lipopolysaccharid (LPS) Gram-negativer Bakterien und transportiert es zu zellulären Rezeptoren, wodurch das angeborene Immunsystem aktiviert wird. In dieser Arbeit wird die Regulation der LBP-Expression in Interleukin (IL)-1, IL-6 und Dexamethason (Dex) stimulierten humanen Hepatomzelllinien HuH-7 und HepG2 untersucht. Der wichtigste Stimulator ist dabei IL-6, dessen Wirkung über die Transkriptionsfaktoren (TF) Stat-3, C/EBP-beta und AP-1 vermittelt wird. Für alle 3 TF konnten aktive Bindungsstellen auf dem LBP-Promotor nachgewiesen werden. Für IL-1-Effekte die u. a. über den TF NF-kappaB vermittelt werden, konnten ebenfalls aktive Bindungsstellen nachgewiesen werden. Die Wirkung von Dex wird über Glucocorticoid Responsive Elements (GREs) vermittelt. Auf dem LBP-Promotor befinden, sich wie gezeigt werden konnte, mehrere aktive GREs, wobei einige verstärkend und einige hemmend wirken. Eine zu beobachtende Synergiewirkung von Dex und IL-6 wird durch die Aufregulation des IL-6-Rezeptors durch Dex verursacht. Die LBP-Expression kann durch TGF (Transforming Growth Factor)-beta gehemmt werden. Der TGF-beta-Signalweg über Smads ist in den Hepatomzellen aktiv, vermittelt aber nicht den TGF-beta-Hemmeffekt, sondern eine geringe stimulierende Wirkung, die bei alleiniger TGF-beta-Inkubation auftritt. Die inhibierende Wirkung von TGF-beta wird durch Gfi-1- und AP-1-Bindungsstellen vermittelt. Die Gfi-1-Bindungsstelle nimmt dabei, wie hier erstmals gezeigt werden konnte, eine herausragende Stellung ein. Die Aufklärung der LBP-Regulation und dabei besonders die Hemmung der LBP-Expression kann mittelfristig dazu beitragen, den klinischen Verlauf von inflammatorischen und infektiösen Erkrankungen zu beeinflussen und bietet daher Potenzial für neue Therapieansätze.Lipopolysaccharide (LPS) binding protein (LBP) is an acute phase protein with the ability to bind and transfer LPS of Gram-negative bacteria. This soluble pattern recognition molecule represents an important defense principle of the host. Regulation of the hepatic acute phase response and its termination are important mechanisms for limiting systemic inflammatory activity of the host. Here were analyze the cooperation of Interleukin (IL)-1, IL-6, and Dexamethasone (Dex) at LBP expression in the hepatoma cell lines HuH-7 and Hep G2. The major inducer of LBP expression is IL-6. Within the LBP promoter numerously highly consensus binding sites such as AP-1, C/EBP-beta? and STAT3 are present, that confer transcriptional activity as shown by truncation and mutation experiments. Additionally, activate NF-kappaB sites activated by IL-1 were detected at the LBP promoter. By mutation experiments of the promoter furthermore were found differentially active glucocorticoid response elements (GREs). The promoter contains GREs enhancing the activity as well as inhibitory ones. The enhancing effect towards LBP expression by Dex was mediated by IL-6. Dex stimulated the expression of the IL-6 receptor and therefore upregulated the IL-6 pathway. Transforming Growth Factor (TGF)-beta is able to inhibit LBP expression in stimulated cells. An AP-1 binding site was identified mediating inhibitory TGF-beta effects towards LBP promoter activity. Furthermore it was shown that a growth factor independence (Gfi)-1 binding site localized near the AP-1 site is essential for mediating the TGF-beta inhibitory effect. The relevancy of the Gfi-1 site fore mediating TGF-beta effects indicates a novel mechanism for understanding inhibitory TGF-beta effects at the transcriptional level. In summary the complex regulation of LBP were elucidate which may help to eventually develop novel intervention strategies for acute phase, sepsis, and septic shock.
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Ho, Wing-man Jessica, and 何詠雯. "Characterization of the 5'flanking region of mitochondrial uncoupling protein 4 (UCP 4) and its relationship with nuclear factor-kappa B(NF-KB) in MPP+ -induced toxicity." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45813346.
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Paquette, Nicholas Paul. "Caspase Mediated Cleavage, IAP Binding, Ubiquitination and Kinase Activation : Defining the Molecular Mechanisms Required for Drosophila NF-кB Signaling: A Dissertation." eScholarship@UMMS, 2009. https://escholarship.umassmed.edu/gsbs_diss/444.
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Innate immunity is the first line of defense against invading pathogens. Vertebrate innate immunity provides both initial protection, and activates adaptive immune responses, including memory. As a result, the study of innate immune signaling is crucial for understanding the interactions between host and pathogen. Unlike mammals, the insect Drosophila melanogasterlack classical adaptive immunity, relying on innate immune signaling via the Toll and IMD pathways to detect and respond to invading pathogens. Once activated these pathways lead to the rapid and robust production of a variety of antimicrobial peptides. These peptides are secreted directly into the hemolymph and assist in clearance of the infection.
The genetic and molecular tools available in the Drosophila system make it an excellent model system for studying immunity. Furthermore, the innate immune signaling pathways used by Drosophilashow strong homology to those of vertebrates making them ideal for the study of activation, regulation and mechanism. Currently a number of questions remain regarding the activation and regulation of both vertebrate and insect innate immune signaling. Over the past years many proteins have been implicated in mammalian and insect innate immune signaling pathways, however the mechanisms by which these proteins function remain largely undetermined.
My work has focused on understanding the molecular mechanisms of innate immune activation in Drosophila. In these studies I have identified a number of novel protein/protein interactions which are vital for the activation and regulation of innate immune induction. This work shows that upon stimulation the Drosophila protein IMD is cleaved by the caspase-8 homologue DREDD. Cleaved IMD then binds the E3 ligase DIAP2 and promotes the K63-polyubiquitination of IMD and activation of downstream signaling. Furthermore the Yersinia pestis effector protein YopJ is able to inhibit the critical IMD pathway MAP3 kinase TAK1 by serine/threonine-acetylation of its activation loop. Lastly TAK1 signaling to the downstream Relish/NF-κB and JNK signaling pathways can be regulated by two isoforms of the TAB2 protein. This work elucidates the molecular mechanism of the IMD signaling pathway and suggests possible mechanisms of homologous mammalian systems, of which the molecular details remain unclear.
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Liu, Ma Feng. "Functional identification of genes involved in heme uptake and utilization in B. henselae." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00833230.
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Les Bartonelles sont des bactéries hémotropes responsables de zoonoses émergentes. Ces Alphaprotéobactéries sont auxotrophes pour l'hème et doivent donc l'importer du milieu extérieur pour croître. Les Bartonelles possèdent un système complet de transport de l'hème permettant de transporter ce composé dans le cytoplasme. Chez Bartonella, il a été montré que l'hème pouvait être utilisé comme source de fer. Comme pour d'autres bactéries utilisant l'hème comme une source de fer, Bartonella doit dégrader l'hème pour libérer le fer. Chez Bartonella, un ensemble de gènes codant pour le système de transport de l'hème, contient un gène codant pour un polypeptide (HemS) présentant des homologies avec des protéines liant ou dégradant l'hème. En utilisant des expériences de complémentation de mutants d'E. coli incapables de dégrader l'hème, nous avons mis en évidence que HemS de Bartonella henselae permet la libération du fer de l'hème. HemS purifié lie l'hème et le dégrade en présence de donneurs d'électrons. La diminution du niveau de HemS chez B. henselae décroit sa capacité de survivre à une exposition à H2O2. Les Bartonelles expriment quatre ou cinq protéines de la membrane externe ayant la capacité de fixer l'hème. Les gènes de structure de ces protéines sont exprimés différemment en fonction de paramètres comme la température ainsi que la concentration en oxygène ou en hème. Ces protéines ont été proposées comme étant impliquées dans divers processus cellulaires étant donné leur profil d'expression. Dans ce manuscrit, nous montrons que ces protéines sont impliquées dans la défense contre le stress oxydatif, la colonisation des cellules endothèliales et la survie dans la puce
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Guidet, François. "Clonage et séquençage des ADNc de la petite sous-unité de la Rubisco et de la LHCP chez Raphanus sativus : leur utilisation comme marqueur de modifications du génome associées au photocontrôle de la transcription." Rouen, 1987. http://www.theses.fr/1987ROUES042.
Full textAbstract:
Deux sondes moléculaires, DNA complémentaire de la petite sous-unité de ribulose-1,5. Bisphosphate carboxylase (PSU) et de la "light harvesting chlorophyll a/b binding proteins" (LHCP) ont été clonées. Leur utilisation a permis de mettre en évidence des modifications du génome reliées à l'état de différenciation et/ou de l'irradiation donnée. La transcription de ces deux polypeptides (PSU) et (LHCP) est régulée par le phytochrome chez le radis (raphanus sativus)
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Ivshina, Maria. "Role of CPEB in Senescence and Inflammation: A Dissertation." eScholarship@UMMS, 2007. http://escholarship.umassmed.edu/gsbs_diss/501.
Full textAbstract:
Cytoplasmic polyadenylation element-binding protein (CPEB) is a sequence-specific RNA-binding protein that promotes polyadenylation-induced translation. While a CPEB knockout (KO) mouse is sterile but overtly normal, embryo fibroblasts derived from this mouse (MEFs) do not enter senescence in culture as do wild-type MEFs, but instead are immortal. Exogenous CPEB restores senescence in the KO MEFs and also induces precocious senescence in wild-type MEFs. CPEB cannot stimulate senescence in MEFs lacking the tumor suppressors p53, p19ARF, or p16INK4A; however, the mRNAs encoding these proteins are unlikely targets of CPEB since their expression is the same in wild-type and KO MEFs. Conversely, Ras cannot induce senescence in MEFs lacking CPEB, suggesting that it may lie upstream of CPEB. One target of CPEB regulation is myc mRNA, whose unregulated translation in the KO MEFs may cause them to bypass senescence. Thus, CPEB appears to act as a translational repressor protein to control myc translation and resulting cellular senescence.
CPEB is a sequence-specific RNA binding protein that regulates cytoplasmic polyadenylation-induced translation. We report here that CPEB KO mice are hypersensitive to LPS-induced endotoxic shock, which correlates with elevated serum levels of the proinflammatory cytokines IL-6, IL-8 and IL-12. Peritoneal macrophages from the KO mice, as well as a CPEB-depleted macrophage cell line, not only secrete more IL-6 than control cells in response to LPS, but also have prolonged retention of NFϰB in the nucleus, which is responsible for elevated IL-6 transcription. The amount of nuclear NFϰB correlates with reduced levels of IϰBα, which is hyperphosphorylated and rapidly degraded. Collectively, these data suggest that CPEB deficiency enhances the inflammatory response via delayed resolution of NFϰB signaling.
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Ivshina, Maria. "Role of CPEB in Senescence and Inflammation: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/501.
Full textAbstract:
Cytoplasmic polyadenylation element-binding protein (CPEB) is a sequence-specific RNA-binding protein that promotes polyadenylation-induced translation. While a CPEB knockout (KO) mouse is sterile but overtly normal, embryo fibroblasts derived from this mouse (MEFs) do not enter senescence in culture as do wild-type MEFs, but instead are immortal. Exogenous CPEB restores senescence in the KO MEFs and also induces precocious senescence in wild-type MEFs. CPEB cannot stimulate senescence in MEFs lacking the tumor suppressors p53, p19ARF, or p16INK4A; however, the mRNAs encoding these proteins are unlikely targets of CPEB since their expression is the same in wild-type and KO MEFs. Conversely, Ras cannot induce senescence in MEFs lacking CPEB, suggesting that it may lie upstream of CPEB. One target of CPEB regulation is myc mRNA, whose unregulated translation in the KO MEFs may cause them to bypass senescence. Thus, CPEB appears to act as a translational repressor protein to control myc translation and resulting cellular senescence.
CPEB is a sequence-specific RNA binding protein that regulates cytoplasmic polyadenylation-induced translation. We report here that CPEB KO mice are hypersensitive to LPS-induced endotoxic shock, which correlates with elevated serum levels of the proinflammatory cytokines IL-6, IL-8 and IL-12. Peritoneal macrophages from the KO mice, as well as a CPEB-depleted macrophage cell line, not only secrete more IL-6 than control cells in response to LPS, but also have prolonged retention of NFϰB in the nucleus, which is responsible for elevated IL-6 transcription. The amount of nuclear NFϰB correlates with reduced levels of IϰBα, which is hyperphosphorylated and rapidly degraded. Collectively, these data suggest that CPEB deficiency enhances the inflammatory response via delayed resolution of NFϰB signaling.
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Mainz, Andi. "Beyond the limit." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16603.
Full textAbstract:
Strukturelle Untersuchungen mittels Lösungs-NMR Spektroskopie sind für supramolekulare Maschinen mit Molekulargewichten von mehr als 150 kDa nur beschränkt möglich. Die Festkörper-NMR mit Probenrotation im sogenannten magischen Winkel (MAS) stellt dagegen eine molekulargewichtsunabhängige Methode dar. Im Rahmen dieser Arbeit wurde eine neue Methode entwickelt, die die MAS NMR Spektroskopie an supramolekularen Komplexen in Lösung erlaubt. Proteinlösungen bilden demnach durch MAS und dessen Ultrazentrifugationseffekt homogene Proteinsedimente aus, in denen die rotatorische Diffusion großer Proteinkomplexe überwiegend aufgehoben ist. Auf diese Weise können klassische Festkörper-NMR Methoden angewandt werden, ohne dass Präzipitations- oder Kristallisationsverfahren erforderlich sind. In Kombination mit Proteindeuterierung, Protonendetektion sowie paramagnetischer Relaxationsverstärkung ermöglichte diese neuartige Methode die Zuordnung von Rückgrat-Amidresonanzen des 20S Proteasoms mit einem Molekulargewicht von 1,1 MDa. Weiterhin wurde diese Methode zur Untersuchung des kleinen Hitzeschockproteins alpha-B-Crystallin und dessen Cu(II)-Bindungseigenschaften genutzt. Das Chaperon (600 kDa) spielt eine wesentliche Rolle in der zellulären Proteinhomeostase. Verschiedenste NMR Techniken und andere biophysikalische Methoden zeigen, dass die konservierte alpha-Crystallin-Domäne ein Cu(II)-Ion nahe der Monomer-Monomer Interaktionsfläche mit pikomolarer Affinität bindet. Die Cu(II)-induzierte Freilegung von Substrat-Interaktionsflächen und Veränderungen in der dynamischen Quartärstruktur modulieren so die oligomere Architektur und die Chaperonaktivität von alpha-B-Crystallin. Die hier erstmals beschriebene MAS NMR Spektroskopie von sedimentierten Biomolekülen legt einen wichtigen Grundstein für zukünftige Struktur- und Dynamikuntersuchungen an großen molekularen Maschinen.Structural investigations of large biomolecules by solution-state NMR are challenging in case the molecular weight of the complex exceeds 150 kDa. Magic-angle-spinning (MAS) solid-state NMR is a powerful tool for the characterization of biomolecular systems irrespective of their molecular weight. In this work, an approach was developed, which enables the investigation of supramolecular modules by MAS NMR. Protein solutions can yield fairly homogeneous sediments due to the ultracentrifugal forces during MAS. Since rotational diffusion is impaired, typical solid-state NMR techniques can thus be applied without the need of precipitation or crystallization. This new approach in combination with protein deuteration, proton-detection and paramagnetic relaxation enhancement enabled the observation and the assignment of backbone amide resonances of a 20S proteasome assembly with a molecular weight of 1.1 MDa. Similarly, the approach was used to characterize the small heat-shock protein alpha-B-crystallin with respect to its Cu(II)-dependent chaperone activity. The chaperone (600 kDa) plays an essential role in cellular protein homeostasis. We show that the conserved alpha-crystallin core domain is the elementary Cu(II)-binding unit specifically coordinating one Cu(II) ion near to the dimer interface with picomolar binding affinity. We suggest that Cu(II)-binding unblocks potential client binding sites and alters quaternary dynamics of both the dimeric building block as well as the higher-order assemblies of alpha-B-crystallin. In summary, MAS NMR employed to biomolecules in solution is a very promising tool to explore structural and dynamic properties of large biological machines with no upper size limit.
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Humphrey, Peter Saah. "Signal transduction mechanisms for stem cell differentation into cardiomyocytes." Thesis, University of Hertfordshire, 2009. http://hdl.handle.net/2299/3760.
Full textAbstract:
Cardiovascular diseases are among the leading causes of death worldwide and particularly in the developed World. The search for new therapeutic approaches for improving the functions of the damaged heart is therefore a critical endeavour. Myocardial infarction, which can lead to heart failure, is associated with irreversible loss of functional cardiomyocytes. The loss of cardiomyocytes poses a major difficulty for treating the damaged heart since terminally differentiated cardiomyocytes have very limited regeneration potential. Currently, the only effective treatment for severe heart failure is heart transplantation but this option is limited by the acute shortage of donor hearts. The high incidence of heart diseases and the scarcity donor hearts underline the urgent need to find alternative therapeutic approaches for treating cardiovascular diseases. Pluripotent embryonic stem (ES) cells can differentiate into functional cardiomyocytes. Therefore the engraftment of ES cell-derived functional cardiomyocytes or cardiac progenitor cells into the damaged heart to regenerate healthy myocardial tissues may be used to treat damaged hearts. Stem cell-based therapy therefore holds a great potential as a very attractive alternative to heart transplant for treating heart failure and other cardiovascular diseases. A major obstacle to the realisation of stem cell-based therapy is the lack of donor cells and this in turn is due to the fact that, currently, the molecular mechanisms or the regulatory signal transduction mechanisms that are responsible for mediating ES cell differentiation into cardiomyocytes are not well understood. Overcoming this huge scientific challenge is absolutely necessary before the use of stem cell-derived cardiomyocytes to treat the damaged heart can become a reality. Therefore the aim of this thesis was to investigate the signal transduction pathways that are involved in the differentiation of stem cells into cardiomyocytes. The first objective was the establishment and use of cardiomyocyte differentiation models using H9c2 cells and P19 stem cells to accomplish the specific objectives of the thesis. The specific objectives of the thesis were, the investigation of the roles of (i) nitric oxide (ii) protein kinase C (PKC), (iii) p38 mitogen-activated protein kinase (p38 MAPK) (vi) phosphoinositide 3-kinase (PI3K) and (vi) nuclear factor-kappa B (NF-kB) signalling pathways in the differentiation of stem cells to cardiomyocytes and, more importantly, to identify where possible any points of convergence and potential cross-talk between pathways that may be critical for differentiation to occur. P19 cells were routinely cultured in alpha minimal essential medium (α-MEM) supplemented with 100 units/ml penicillin /100 μg/ml streptomycin and 10% foetal bovine serum (FBS). P19 cell differentiation was initiated by culturing the cells in microbiological plates in medium containing 0.8 % DMSO to form embryoid bodies (EB). This was followed by transfer of EBs to cell culture grade dishes after four days. H9c2 cells were cultured in Dulbecco’s Modified Eagle’s medium (DMEM) supplemented with 10% FBS. Differentiation was initiated by incubating the cells in medium containing 1% FBS. In both models, when drugs were employed, they were added to cells for one hour prior to initiating differentiation. Cell monolayers were monitored daily over a period of 12 or 14 days. H9c2 cells were monitored for morphological changes and P19 cells were monitored for beating cardiomyocytes. Lysates were generated in parallel for western blot analysis of changes in cardiac myosin heavy chain (MHC), ventricular myosin chain light chain 1(MLC-1v) or troponin I (cTnI) using specific monoclonal antibodies. H9c2 cells cultured in 1% serum underwent differentiation as shown by the timedependent formation of myotubes, accompanied by a parallel increase in expression of both MHC and MLC-1v. These changes were however not apparent until 4 to 6 days after growth arrest and increased with time, reaching a peak at day 12 to 14. P19 stem cells cultured in DMSO containing medium differentiated as shown by the timedependent appearance of beating cardiomyocytes and this was accompanied by the expression of cTnI. The differentiation of both P19 stem cells and H9c2 into cardiomyocytes was blocked by the PI3K inhibitor LY294002, PKC inhibitor BIM-I and the p38 MAPK inhibitor SB2035800. However when LY294002, BIM-I or SB2035800 were added after the initiation of DMSO-induced P19 stem cell differentiation, each inhibitor failed to block the cell differentiation into beating cardiomyocytes. The NF-kB activation inhibitor, CAPE, blocked H9c2 cell differentiation into cardiomyocytes. Fast nitric oxide releasing donors (SIN-1 and NOC-5) markedly delayed the onset of differentiation of H9c2 cells into cardiomyocytes while slow nitric oxide releasing donors (SNAP and NOC-18) were less effective in delaying the onset of differentiation or long term differentiation of H9c2 cells into cardiomyocytes. Akt (protein kinase B) is the key downstream target of PI3K. Our cross-talk data also showed that PKC inhibition and p38 MAPK inhibition respectively enhanced and reduced the activation of Akt, as determined by the phosphorylation of Akt at serine residue 473. In conclusion, PKC, PI3K, p38 MAPK and NF-kB are relevant for the differentiation of stem cells into cardiomyocytes. Our data also show that the PKC, PI3K and p38 MAPK signalling pathways are activated as very early events during the differentiation of stem cells into cardiomyocytes. Our data also suggest that PKC may negatively regulate Akt activation while p38 MAPK inhibition inhibits Akt activation. Our fast NO releasing donor data suggest that nitric oxide may negatively regulate H9c2 cell differentiation.
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Wang, Shin-Mei, and 王馨梅. "Studies on the gene expression of chlorophyll a/b-binding protein(LhcII) and photosystem I subunit III (psaF) in Ulva fasciata." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/32c28n.
Full textAbstract:
碩士國立中山大學
海洋生物研究所
95
The study was to investigated the gene expression of light harvesting complex II (LhcII) of photosystem II (PSII) and Photosystem I reaction center subunit III (psaF) in the marine macroalga Ulva fasciata Delile in relation to copper (50 μM CuSO4) and hypersalinity (90‰ ASW) stress. Excess copper had little effect on photosynthetic ability and gene expression of LhcII and psaF. Hypersaline decreased Fv/Fm and Fv''/Fm'', but increased LhcII and psaF transcript level to a plateau after 6 h. The effects of ROS scavengers(5 mM dimethylthiourea (DMTU)、10 mM 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron) or 10 mM sodium benzoate (SB) to 90‰-grown thalli) on LhcII and psaF gene expression were examined by exogenous application of. Indicate that O2•－ is the factor for mediating LhcII gene expression by 90‰ while O2•－、H2O2 and OH• are related to the induction of psaF gene expression by hypersalinity. Exogenously applied spermidine (Spd) and spermine (Spm) recovered Fv/Fm and Fv''/Fm'' and decreased LhcII and psaF transcript levels by 90‰ while putrescine (Put) recovered only Fv''/Fm'' but not effect on Fv/Fm and LhcII transcript levels were increased. Electron-transport inhibitors, 50 μM 3-(3,4 dichlorophenyl) -1,1-dimethyl urea (DCMU) or 50 μM 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) , applied to the 30‰-grown thalli decreased Fv/Fm and Fv''/Fm'' but increased LhcII transcript levels while psaF transcript levels were decreased.It could be concluded that the expression of LhcII and psaF were influenced by the redox state of plastoquinone pool (PQ pool) and photosynthetic electron flow ; Reactive oxygen species produced under hypersaline condition influenced the LhcII and psaF transcript level, and polyamine might play a protective role against salt stress by the modulation of LhcII and psaF gene expression.
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Liao, Chong-Fu, and 廖崇富. "Identification and Characterization of Brassica oleracea var. capitata Chlorophyll a/b Binding Protein Bound to Trichoderma harzianum ETS 323 L-Amino Acid Oxidase." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/x8az9s.
Full textAbstract:
碩士國立東華大學
生命科學系
107
T. harzianum ETS 323 is a well-known environmental biological control agent. Its mechanisms mainly contributes to production of extracellular proteins, secondary metabolites and resistance induction. Among these, L-amino acid oxidase and chrysophanol have been proven antibiotic activities and resistance induction of Brassica oleracea. The further interest would be to investigating binding proteins of the B. oleracea to ThLAAO. By using ThLAAO affiliated affinity chromatography, a 28.3 kDa ThLAAO binding membrane protein of B. oleracea was isolated and identified as Chlorophyll a/b binding protein. In the present of the ThLAAO, later infected with Botrytis cinerea, cab expression of B. oleracea leaf increase 2.5 folds, the cab of B. oleracea leaf that treated with His6-CAB later infection B. cinerea decreasing 7 folds. A mole ratio 1:1 of ThLAAO and His6-CAB mixture was applied to the B. oleracea leaf later infected with B. cinerea showing that His6-CAB can antagonize the ThLAAO resistance induction capability corresponding to decreasing cab expression 10 folds. The percentage of infection area of B. oleracea leaf were ThLAAO is 0 to 15 ％ His6-CAB is 50 to 100 ％ and ThLAAO mixture with His6-CAB is 70 to 100 ％accordingly decrease cab expression, respectively. ThLAAO-Cy5.5 treated B. oleracea root showing that ThLAAO-Cy5.5 enter root and transport to the leaves where have been proven in chloroplast in other investigation. This study showed that B. oleracea chlorophyll a/b binding protein is the binding protein of T. harzianum ETS 323 L-amino acid oxidase that induces pathogen resistance.
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BUČINSKÁ, Lenka. "Biosynthesis of chlorophyll-binding proteins in cyanobacteria." Doctoral thesis, 2019. http://www.nusl.cz/ntk/nusl-393315.
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In oxygenic phototrophs, the photosynthetic machinery is located in thylakoid membrane (TM), a specialized endogenous membrane system. How TM are synthesized remains however mostly unknown. The aim of this thesis was to clarify a link between the synthesis of chlorophyll (Chl)-binding proteins, the main protein component of TM, and the formation of TM system in the model cyanobacterium Synechocystis PCC 6803. During the project, the analysis of TM under various growth conditions and in Chl-deficient mutants has demonstrated that a sufficient amount of de novo produced Chl molecules is crucial for the TM biogenesis. Particularly, the synthesis of the photosystem II subunit CP47 and trimeric photosystem I appeared to be sensitive to a shortage in de novo made Chl molecules. Interestingly, a specialized ribosome-binding protein (Pam68) has been identified to facilitate the insertion of Chl molecules into CP47. The synthesis of Chl-proteins and the biogenesis of TM have been further explored in cells recovering from long-term nitrogen depletion. Using this approach, it was possible to identify a large structure in the cell cytosol, which is very likely the site of TM biogenesis, and to correlate the appearance of this structure with the restored biogenesis of Chl-binding proteins.
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Schmidt, Kristin [Verfasser]. "Pigmentbindung verschiedener Mitglieder der erweiterten Chlorophyll-a-b-Proteinfamilie und des wasserlöslichen Chlorophyll-Proteins WSCP / Kristin Schmidt." 2003. http://d-nb.info/968710921/34.
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Kretschmer, Jens. "Interactions and functions of RNA-binding proteins." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E3B9-B.
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KOPEČNÁ, Jana. "Regulation of the chlorophyll biosynthesis in the cyanobacterium \kur{Synechocystis} sp. PCC 6803." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-135192.
Full textAbstract:
The thesis focuses on regulation of the chlorophyll biosynthetic pathway and its coordination with synthesis of chlorophyll-binding proteins in the cyanobacterium Synechocystis sp. PCC 6803. One of the aims was to analyze correlation between syntheses of photosystems and chlorophyll in Synechocystis cells using radioactive labeling of proteins and chlorophyll by 35S and 14C, respectively. I also investigated the role of enzymes catalyzing protochlorophyllide reduction step in the chlorophyll biosynthesis by analyzing the synthesis and accumulation of photosynthetic proteins in Synechocystis mutants lacking one of the enzymes. Further, roles of Ycf54 and Psb27 proteins in stability and assembly of oxidative cyclase and CP43, respectively, are also described.
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Chorghade, Sandip Gulab. "Studies on Interactions between ARE Binding Proteins and Splicing Factors and their Role in Altered Splicing of PDGF-B ORF." Thesis, 2012. http://hdl.handle.net/2005/3227.
Full textAbstract:
Pre-mRNA splicing is an important level in posttranscriptional gene regulation that is essential for accurate protein synthesis and generating protein diversity. The abundance of cryptic splice sites and long intronic DNA sequences makes their splicing a complex one. The identification of correct exons and introns needs additional information in the form of splicing regulatory elements (SREs) along with canonical splice signals. The interplay among these SREs and the trans factors (which bind to SREs) gives the identity to introns and exons which in turn leads to precise pre-mRNA splicing.
Previous studies from our laboratory showed, that when expressed in mammalian cells from an expression vector, PDGF-B ORF was re-spliced at 4/5 exon junction with the downstream SV40 splice acceptor site in the vector. However, deletion of the 66-nt PDGF-B 3’ UTR region resulted in about 25% reduction in re-splicing. Sequence analysis of this region revealed presence of binding sites for splicing factors ASF/SF2 and SRp55, and an AU-rich element (ARE), mutation each of which affected re-splicing partially. In mammals, AREs are commonly found in the 3’UTR of mRNAs encoding proteins involved in diverse functions and are involved in selective mRNA degradation. Several ARE binding proteins are crucial for ARE’s function. Since mutation of the single ARE in the 3’UTR region altered the re-splicing efficiency, the role of AU-rich elements and ARE-binding proteins (AU-BPs) in modulation of splicing was investigated using siRNAs against AU-BPs, BRF1, hnRNPD, HuR, GAPDH and TTP. Down regulation of expression of these factors indeed affected the level of re-spliced product.
We have studied the interactions between the full-length splicing factors (U1-70K and U2AF35) and the AU-BPs (BRF1, hnRNPD and HuR) as well as among the AU-BPs using three different assay methods: Yeast-two hybrid, co-immunoprecipitation and pull down assays. Our study has revealed that the BRF1 interacts with U1-70K and U2AF35 as well as the other AU-BPs hnRNPD and HuR but with different affinities. We have also analyzed the ability of AU-BPs to interact with SR proteins SRp20 and 9G8. We did find strong interaction of BRF1 with SRp20 and 9G8.
Generation of a large number of nested deletion mutants of all the proteins allowed us to identify the interaction regions on the surface of BRF1, U1-70K, hnRNPD, U2AF35 and HuR. The results of Y2H analyses were further confirmed by pull down assay using purified interacting regions.
It was found that a single region from aa 181-254 in BRF1 interacts with multiple partners i.e., splicing factors and the AU-BP hnRNPD. However, the RNA-binding zinc-finger domain from residue 120-181 independently interacts with HuR. Further, the multiple protein interacting region (MPIR) (aa 181-254) in BRF1 exhibits different affinities towards its interacting partners with that for U1-70K and hnRNPD being stronger than that for U2AF35 and HuR. This observation suggests that BRF1 activity can be modulated by interaction with different partners at different sites.
U1-70K interacted only with BRF1 among the proteins tested in this study and this interaction appears to be RNA independent .This could have implications in splice site selection and RNA stability since BRF1 has been shown to promote RNA degradation. While the Arg/Glu-rich C-terminal region in U1-70K is sufficient for its interaction with BRF1, U2AF35 requires both the zinc-finger 2 and the arg/Gly/Ser-rich C-terminal regions for its association with BRF1.
hnRNPD also interacts with multiple partners that include BRF1, HuR and U2AF35 using the N-terminal region that harbors a Ala-rich domain. The interaction of hnRNPD with HuR is RNA dependent while with BRF1 and U2AF35, it is RNA independentt. Further, its interaction with all the partners is equally strong. This suggests that hnRNPD could exert differential influence depending on the context of its interaction and abundance of the interacting partner.
HuR, primarily known as an mRNA stabilizing factor, interacts with both BRF1 and hnRNPD with equal affinity involving the hinge region, the interaction with the former being RNA-independent and the later being RNA-dependent. This differential RNA-dependent and independent interactions with the two AU-BPs using a single interacting domain suggests a balancing act of HuR on the activities of BRF1 and hnRNPD. These interactions can further be differentially modulated by posttranslational modifications on one or all of the interacting partners depending on the physiological status of the cell.
We have also analyzed the multiple protein complexes formed in absence of cellular RNA. Though we are unable to see direct protein-protein interaction between HuR and U1-70K in Yeast two hybrid analysis, we could detect the presence of U1-70K in HuR immunoprecipitate. It appears that U1-70K associates with HuR via BRF. We also detected the presence of HuR in U1-70K complexes which could be due to its association with BRF1. We are unable to find hnRNPD and U2AF35 in these complexes indicating that they may have been excluded. In anti-U2AF35 immunoprecipitates, we detected the presence of U1-70K as well as hnRNPD but no HuR. This may be due to RNase treatment as hnRNPD and HuR interactions are RNA dependent.
Our findings that AU-rich elements in conjunction with AU-BPs function as intronic splicing modulators or enhancers, reveal hitherto unidentified new players in the poorly understood complex mechanisms that mediate alternative splicing. The possibility of dynamic nature of the interactions among splicing factors and AU-BPs mediated by post-translational modifications provide a basis for rapid cellular responses to changing environmental cues through generation of differentially spliced mRNAs and corresponding protein products that differ in their stability and hence their relative abundance. Our results also unfold enormous possibilities for future investigations on interactions among the many splicing factors and AU-BPs, and in understanding these complex interactions in modulation of pre-mRNA splicing, mRNA translation and degradation. The finding of coupling of AU-BPs to splicing machinery could further lead to better understanding of the mechanism of AU-BP-mediated targeting of mRNAs to processing bodies and ultimate degradation of the mRNAs.
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Chen, Grace Yi-Ying. "Functional Analysis of Adapter Protein c-Abl Src Homology 3 Domain-binding Protein 2." Thesis, 2009. http://hdl.handle.net/1807/17740.
Full textAbstract:
3BP2 is a pleckstrin homology (PH) domain- and Src homology 2 (SH2) domain-containing adapter protein that has been linked through genetic evidence to a rare human disease called cherubism 146. 3BP2 was originally cloned in a screen to identify c-Abl SH3 binding proteins 23,24. In overexpression studies, 3BP2 has been implicated as a positive regulatory adapter molecule coupled to immunoreceptor on T cells 67,69,70, B cells 68, NK cells 71-73 and mast cells 74,75. It was also evident that 3BP2 forms complexes with a number of signaling molecules, such as Zap-70, LAT, phospholipase C-γ1 (PLC-γ1), Grb2, Cbl, and Fyn in Jurkat cells 67 and Vav1, Vav2, PLC-γ, and Syk in Daudi B cells 68.
Despite the growing body of biochemical data to support the importance of 3BP2 in cells of the hematopoietic lineage, a clear picture of the biological function of 3BP2 has yet to emerge. To elucidate the in vivo function of 3BP2, our laboratory has generated 3BP2 gene-deficient mice through homologous recombination 452. The 3BP2-deficient (3BP2-/-) mice were born at the expected Mendelian frequency and were fertile and viable.
3BP2-/- mice accumulate splenic marginal-zone (MZ) B cells, possess a reduced frequency of peritoneal B-1 B cells, and have a diminished thymus-independent type 2 (TI-2) antigen response. 3BP2-/- B cells demonstrate diminished proliferation and cell survival following cross-linking of the B-cell receptor (BCR). Following BCR ligation, 3BP2 might be recruited to BCR complex through its inducible interaction with BCR costimulatory molecule CD19. In the absence of 3BP2, the activation of BCR downstream effectors such as MAPK Erk1/2, JNK, and c-Abl is normal; however, 3BP2 deficiency leads to defects in Syk phosphorylation and calcium flux.
In addition to defects in peripheral B cell activities, 3BP2 deficiency contributes to defects in neutrophil activities. In response to the chemotactic peptide, fMLF, 3BP2-/- neutrophils fail to establish directional migration in vitro. There is a defect in the accumulation of filamentous actin at the leading edge of migrating 3BP2-/- neutrophils which might be responsible for the random movement of these cells under shallow gradient of fMLF. In vivo, there is a delay in the recruitment of circulating neutrophils to the site of chemically induced inflammation in 3BP2-/- mice. Compared to wildtype neutrophils, 3BP2-/- neutrophils fail to properly produce superoxide anion (O2-) following fMLF stimulation. Defects in both directional migration and superoxide production of 3BP2-/- neutrophils might contribute to the reduction in bacteria clearance and the increased mortality in 3BP2-/- mice post Listeria Monocytogenes infection.
In Chapter 1 of this thesis, I have reviewed basic structures and functions of the domain modules found in adapter proteins. In addition, I have reviewed the findings from numerous reports on the function of 3BP2 in different cell types. A discussion of the physical appearance and some of the initial characterization of 3BP2-deficient mice (3BP2-/-) we have generated in our laboratory are included in Chapter 1. The second part of Chapter 1 consists of an introduction on B cell receptor signaling pathway and B-cell development and activation. A discussion of G protein-coupled receptor-mediated neutrophil functions can also be found in Chapter 1.
Chapter 2 contains all the methods and materials used in my study.
Chapter 3 includes the characterization of peripheral B cell compartment of 3BP2-/- mice as well as the role of 3BP2 downstream of B-cell antigen receptor and in T-independent immune response.
In chapter 4, I present data from experiments designed to examine the role of 3BP2 downstream of a G protein-coupled receptor, fMLF receptor, of neutrophils. I also show the requirement of 3BP2 in the clearance of Listeria Monocytogenes.
In chapter 5, I propose two models for 3BP2 action based on the findings in B cells and neutrophils and discuss future areas for investigation.
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Mahl, Sarah Elisabeth. "The role of TAL1 and the atypical NF-KB heterodimer p65/c-Rel in T-cell acute lymphoblastic leukemia." 2013. http://liblink.bsu.edu/uhtbin/catkey/1728249.
Full textAbstract:
T-ALL accounts for 15% of childhood leukemias and approximately 60% of patients overexpress TAL1. TAL1/SCL encodes a transcription factor that regulates hematopoiesis by dimerizing with additional transcription factors including E12, E47, and GATA-1. TAL1 has also been found to repress expression of NF-κB1, potentially promoting formation of an NF-κB p65/c-Rel heterodimer that encourages cell survival by up-regulating IAPs and IκB. However, the correlation between TAL1 and p65/c-Rel expression and their effects on downstream targets like IKK, IκB, and other anti-apoptotic proteins is poorly understood. Jurkat cells, expressing TAL1, were treated with TNFα and/or etoposide to induce apoptosis and experiments were performed to assess the expression of proteins of interest. Caspase-8 activity assays were also performed to help delineate the apoptotic signal present in these cells. Determining if interactions between TAL1, NF-κB, and other downstream targets help promote apoptotic resistance will further research into better, more targeted treatments for T-ALL.Department of Biology