Journal articles: 'Mating type locus'

1

Staben, Chuck. "The mating-type locus ofNeurospora crassa." Journal of Genetics 75, no. 3 (December 1996): 341–50. http://dx.doi.org/10.1007/bf02966313.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Foulongne-Oriol, Marie, Ozgur Taskent, Ursula Kües, Anton S. M. Sonnenberg, Arend F. van Peer, and Tatiana Giraud. "Mating-Type Locus Organization and Mating-Type Chromosome Differentiation in the Bipolar Edible Button Mushroom Agaricus bisporus." Genes 12, no. 7 (July 16, 2021): 1079. http://dx.doi.org/10.3390/genes12071079.

Full text

Abstract:

In heterothallic basidiomycete fungi, sexual compatibility is restricted by mating types, typically controlled by two loci: PR, encoding pheromone precursors and pheromone receptors, and HD, encoding two types of homeodomain transcription factors. We analysed the single mating-type locus of the commercial button mushroom variety, Agaricus bisporus var. bisporus, and of the related variety burnettii. We identified the location of the mating-type locus using genetic map and genome information, corresponding to the HD locus, the PR locus having lost its mating-type role. We found the mip1 and β-fg genes flanking the HD genes as in several Agaricomycetes, two copies of the β-fg gene, an additional HD2 copy in the reference genome of A. bisporus var. bisporus and an additional HD1 copy in the reference genome of A. bisporus var. burnettii. We detected a 140 kb-long inversion between mating types in an A. bisporus var. burnettii heterokaryon, trapping the HD genes, the mip1 gene and fragments of additional genes. The two varieties had islands of transposable elements at the mating-type locus, spanning 35 kb in the A. bisporus var. burnettii reference genome. Linkage analyses showed a region with low recombination in the mating-type locus region in the A. bisporus var. burnettii variety. We found high differentiation between β-fg alleles in both varieties, indicating an ancient event of recombination suppression, followed more recently by a suppression of recombination at the mip1 gene through the inversion in A. bisporus var. burnettii and a suppression of recombination across whole chromosomes in A. bisporus var. bisporus, constituting stepwise recombination suppression as in many other mating-type chromosomes and sex chromosomes.

APA, Harvard, Vancouver, ISO, and other styles

3

Judelson, H. S., L. J. Spielman, and R. C. Shattock. "Genetic mapping and non-Mendelian segregation of mating type loci in the oomycete, Phytophthora infestans." Genetics 141, no. 2 (October 1, 1995): 503–12. http://dx.doi.org/10.1093/genetics/141.2.503.

Full text

Abstract:

Abstract DNA markers linked to the determinants of mating type in the oomycete, Phytophthora infestans, were identified and used to address the genetic basis of heterothallism in the normally diploid fungus. Thirteen loci linked to the A1 and A2 mating types were initially identified by bulked segregant analysis using random amplified polymorphic DNA markers (RAPDs) and subsequently scored in three crosses polymorphisms (SSCP), cleaved amplified polymorphisms (CAPS), or allele-specific polymerase chain reaction markers (AS-PCR). All DNA markers mapped to a single region, consistent with a single locus determining both mating types. Long-range restriction mapping also demonstrated the linkage of the markers to one region and delimited the mating type locus to a 100-kb region. The interval containing the mating type locus displayed non-Mendelian segregation as only two of the four expected genotypes were detected in progeny. This is consistent with a system of balance lethal loci near the mating type locus. A model for mating type determination is presented in which the balanced lethals exclude form progeny those with potentially conflicting combinations of mating type alleles, such as those simultaneously expressing A1 and A2 functions.

APA, Harvard, Vancouver, ISO, and other styles

4

Kanamori, Masaki, Hana Kato, Nobuko Yasuda, Shinzo Koizumi, Tobin L. Peever, Takashi Kamakura, Tohru Teraoka, and Tsutomu Arie. "Novel mating type-dependent transcripts at the mating type locus in Magnaporthe oryzae." Gene 403, no. 1-2 (November 2007): 6–17. http://dx.doi.org/10.1016/j.gene.2007.06.015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Judelson, Howard S. "Genetic and Physical Variability at the Mating Type Locus of the Oomycete, Phytophthora infestans." Genetics 144, no. 3 (November 1, 1996): 1005–13. http://dx.doi.org/10.1093/genetics/144.3.1005.

Full text

Abstract:

Abstract Mating type in the oomyceteous fungus, Phytophthora infestans, is determined by a single locus. In a previous study of a few isolates, the locus segregated in a manner genetically consistent with its linkage to a system of balanced lethal loci. To determine the prevalence of this phenomenon within P. infestans, genetic analyses were performed using isolates representative of the diversity within the species that had been selected by DNA fingerprinting using probes linked to mating type. Non-Mendelian segregation of the mating type locus was observed in crosses performed with each isolate. An unusual group of isolates was identified in which the mating type determinants had been rearranged within the genome; these strains also produced an aberrantly large number of self-fertile progeny. Curiously, in all isolates, markers linked to the mating type locus appeared prone to duplication, transposition, deletion, or other rearrangement. This was not observed for loci unlinked to mating type. Data from the crosses and analyses of marker variation were used to erect models to explain the bases of mating type determination and of the unusual segregation of the chromosomal region containing the mating type locus.

APA, Harvard, Vancouver, ISO, and other styles

6

Lengeler, Klaus B., Deborah S. Fox, James A. Fraser, Andria Allen, Keri Forrester, Fred S. Dietrich, and Joseph Heitman. "Mating-Type Locus of Cryptococcus neoformans: a Step in the Evolution of Sex Chromosomes." Eukaryotic Cell 1, no. 5 (October 2002): 704–18. http://dx.doi.org/10.1128/ec.1.5.704-718.2002.

Full text

Abstract:

ABSTRACT The sexual development and virulence of the fungal pathogen Cryptococcus neoformans is controlled by a bipolar mating system determined by a single locus that exists in two alleles, α and a. The α and a mating-type alleles from two divergent varieties were cloned and sequenced. The C. neoformans mating-type locus is unique, spans >100 kb, and contains more than 20 genes. MAT-encoded products include homologs of regulators of sexual development in other fungi, pheromone and pheromone receptors, divergent components of a MAP kinase cascade, and other proteins with no obvious function in mating. The α and a alleles of the mating-type locus have extensively rearranged during evolution and strain divergence but are stable during genetic crosses and in the population. The C. neoformans mating-type locus is strikingly different from the other known fungal mating-type loci, sharing features with the self-incompatibility systems and sex chromosomes of algae, plants, and animals. Our study establishes a new paradigm for mating-type loci in fungi with implications for the evolution of cell identity and self/nonself recognition.

APA, Harvard, Vancouver, ISO, and other styles

7

LUDWIG, Lars R., Tina C. SUMMERFIELD, Janice M. LORD, and Garima SINGH. "Characterization of the mating-type locus (MAT) reveals a heterothallic mating system inKnightiella splachnirima." Lichenologist 49, no. 4 (July 2017): 373–85. http://dx.doi.org/10.1017/s0024282917000214.

Full text

Abstract:

AbstractIn the present study, we characterized the mating-type locus ofKnightiella splachnirima(Icmadophilaceae) using degenerate and inverse PCR techniques. We screened for the presence of both mating-type locus idiomorphs in DNA extracts of minuscule samples of haploid thalline tissue. We found that only one of the two idiomorphs was present in each sample, and the mating-type ratio (MAT1-1:MAT1-2) was very balanced, being 8:10 and 13:14 at local and global scales, respectively. This indicates that the species is probably self-incompatible and requires the presence of compatible mating partners for sexual reproduction (heterothallic mating system). Furthermore, we provide a mating-type screening protocol withK. splachnirimaspecific mating-type locus primers, which could serve as an essential tool for the conservation management of this rare Australasian endemic.

APA, Harvard, Vancouver, ISO, and other styles

8

Bubnick, Meggan, and A. George Smulian. "The MAT1 Locus of Histoplasma capsulatum Is Responsive in a Mating Type-Specific Manner." Eukaryotic Cell 6, no. 4 (February 23, 2007): 616–21. http://dx.doi.org/10.1128/ec.00020-07.

Full text

Abstract:

ABSTRACT Recombination events associated with sexual replication in pathogens may generate new strains with altered virulence. Histoplasma capsulatum is a mating-competent, pathogenic fungus with two described phenotypic mating types, + and −. The mating (MAT) locus of H. capsulatum was identified to facilitate molecular studies of mating in this organism. Through syntenic analysis of the H. capsulatum genomic sequence databases, a MAT1-1 idiomorph region was identified in H. capsulatum strains G217B and WU24, and a MAT1-2 idiomorph region was identified in the strain G186AR. A mating type-specific PCR assay was developed, and two clinical isolates of opposite genotypic mating type, UH1 and VA1, were identified. A known − mating type strain, T-3-1 (ATCC 22635), was demonstrated to be of MAT1-2 genotypic mating type. The clinical isolates UH1 and VA1 were found to be mating compatible and also displayed mating-type-dependent regulation of the MAT transcription factors in response to extracts predicted to contain mating pheromones. These studies support a role for the identified MAT1 locus in determining mating type in H. capsulatum.

APA, Harvard, Vancouver, ISO, and other styles

9

Zambino, Paul, James V. Groth, Lewis Lukens, James R. Garton, and Georgiana May. "Variation at the b Mating Type Locus of Ustilago maydis." Phytopathology® 87, no. 12 (December 1997): 1233–39. http://dx.doi.org/10.1094/phyto.1997.87.12.1233.

Full text

Abstract:

Population level diversity at the Ustilago maydis b mating type locus was determined in samples from four Minnesota locations using a combination of plate mating techniques and a polymerase chain reaction (PCR)-based assay. The PCR method allows rapid identification of b types from samples of natural populations and utilizes the hypervariable regions of the b locus that determine mating type specificity. Results demonstrated high levels of b diversity within populations, with one population yielding 17 of the total 18 b types found in the study. Pairwise GST values were in the range of 0.02 to 0.05, and common b mating types were found across broad geographic distances. These data demonstrated that very low levels of differentiation among U. maydis populations occur with respect to b locus variation. Consistent with frequency-dependent selection models, b types were represented at approximately equal frequencies within the entire Minnesota population. However, neutral evolutionary models for patterns of geographic distribution and variation at b cannot be entirely excluded. The importance to agricultural practices of understanding population genetic processes is discussed.

APA, Harvard, Vancouver, ISO, and other styles

10

Chaleff, D. T., and K. Tatchell. "Molecular cloning and characterization of the STE7 and STE11 genes of Saccharomyces cerevisiae." Molecular and Cellular Biology 5, no. 8 (August 1985): 1878–86. http://dx.doi.org/10.1128/mcb.5.8.1878.

Full text

Abstract:

In the yeast Saccharomyces cerevisiae, haploid cells occur in one of the two cell types, a or alpha. The allele present at the mating type (MAT) locus plays a prominent role in the control of cell type expression. An important consequence of the elaboration of cell type is the ability of cells of one mating type to conjugate with cells of the opposite mating type, resulting in yet a third cell type, an a/alpha diploid. Numerous genes that are involved in the expression of cell type and the conjugation process have been identified by standard genetic techniques. Molecular analysis has shown that expression of several of these genes is subject to control on the transcriptional level by the MAT locus. Two genes, STE7 and STE11, are required for mating in both haploid cell types; ste7 and ste11 mutants are sterile. We report here the molecular cloning of STE7 and STE11 genes and show that expression of these genes is not regulated transcriptionally by the MAT locus. We also have genetically mapped the STE11 gene to chromosome XII, 40 centimorgans from ura4.

APA, Harvard, Vancouver, ISO, and other styles

11

Chaleff, D. T., and K. Tatchell. "Molecular cloning and characterization of the STE7 and STE11 genes of Saccharomyces cerevisiae." Molecular and Cellular Biology 5, no. 8 (August 1985): 1878–86. http://dx.doi.org/10.1128/mcb.5.8.1878-1886.1985.

Full text

Abstract:

In the yeast Saccharomyces cerevisiae, haploid cells occur in one of the two cell types, a or alpha. The allele present at the mating type (MAT) locus plays a prominent role in the control of cell type expression. An important consequence of the elaboration of cell type is the ability of cells of one mating type to conjugate with cells of the opposite mating type, resulting in yet a third cell type, an a/alpha diploid. Numerous genes that are involved in the expression of cell type and the conjugation process have been identified by standard genetic techniques. Molecular analysis has shown that expression of several of these genes is subject to control on the transcriptional level by the MAT locus. Two genes, STE7 and STE11, are required for mating in both haploid cell types; ste7 and ste11 mutants are sterile. We report here the molecular cloning of STE7 and STE11 genes and show that expression of these genes is not regulated transcriptionally by the MAT locus. We also have genetically mapped the STE11 gene to chromosome XII, 40 centimorgans from ura4.

APA, Harvard, Vancouver, ISO, and other styles

12

Moore, T. D., and J. C. Edman. "The alpha-mating type locus of Cryptococcus neoformans contains a peptide pheromone gene." Molecular and Cellular Biology 13, no. 3 (March 1993): 1962–70. http://dx.doi.org/10.1128/mcb.13.3.1962.

Full text

Abstract:

The opportunistic fungal pathogen Cryptococcus neoformans has two mating types, MATa and MAT alpha. The MAT alpha strains are more virulent. Mating of opposite mating type haploid yeast cells results in the production of a filamentous hyphal phase. The MAT alpha locus has been isolated in this study in order to identify the genetic differences between mating types and their contribution to virulence. A 138-bp fragment of MAT alpha-specific DNA which cosegregates with alpha-mating type was isolated by using a difference cloning method. Overlapping phage and cosmid clones spanning the entire MAT alpha locus were isolated by using this MAT alpha-specific fragment as a probe. Mapping of these clones physically defined the MAT alpha locus to a 35- to 45-kb region which is present only in MAT alpha strains. Transformation studies with fragments of the MAT alpha locus identified a 2.1-kb XbaI-HindIII fragment that directs starvation-induced filament formation in MATa cells but not in MAT alpha cells. This 2.1-kb fragment contains a gene, MF alpha, with a small open reading frame encoding a pheromone precursor similar to the lipoprotein mating factors found in Saccharomyces cerevisiae, Ustilago maydis, and Schizosaccharomyces pombe. The ability of the MATa cells to express, process, and secrete the MAT alpha pheromone in response to starvation suggests similar mechanisms for these processes in both cell types. These results also suggest that the production of pheromone is under a type of nutritional control shared by the two cell types.

APA, Harvard, Vancouver, ISO, and other styles

13

Moore, T. D., and J. C. Edman. "The alpha-mating type locus of Cryptococcus neoformans contains a peptide pheromone gene." Molecular and Cellular Biology 13, no. 3 (March 1993): 1962–70. http://dx.doi.org/10.1128/mcb.13.3.1962-1970.1993.

Full text

Abstract:

The opportunistic fungal pathogen Cryptococcus neoformans has two mating types, MATa and MAT alpha. The MAT alpha strains are more virulent. Mating of opposite mating type haploid yeast cells results in the production of a filamentous hyphal phase. The MAT alpha locus has been isolated in this study in order to identify the genetic differences between mating types and their contribution to virulence. A 138-bp fragment of MAT alpha-specific DNA which cosegregates with alpha-mating type was isolated by using a difference cloning method. Overlapping phage and cosmid clones spanning the entire MAT alpha locus were isolated by using this MAT alpha-specific fragment as a probe. Mapping of these clones physically defined the MAT alpha locus to a 35- to 45-kb region which is present only in MAT alpha strains. Transformation studies with fragments of the MAT alpha locus identified a 2.1-kb XbaI-HindIII fragment that directs starvation-induced filament formation in MATa cells but not in MAT alpha cells. This 2.1-kb fragment contains a gene, MF alpha, with a small open reading frame encoding a pheromone precursor similar to the lipoprotein mating factors found in Saccharomyces cerevisiae, Ustilago maydis, and Schizosaccharomyces pombe. The ability of the MATa cells to express, process, and secrete the MAT alpha pheromone in response to starvation suggests similar mechanisms for these processes in both cell types. These results also suggest that the production of pheromone is under a type of nutritional control shared by the two cell types.

APA, Harvard, Vancouver, ISO, and other styles

14

Wang, Jinliang, and William G. Hill. "Effect of Selection Against Deleterious Mutations on the Decline in Heterozygosity at Neutral Loci in Closely Inbreeding Populations." Genetics 153, no. 3 (November 1, 1999): 1475–89. http://dx.doi.org/10.1093/genetics/153.3.1475.

Full text

Abstract:

Abstract Transition matrices for selfing and full-sib mating were derived to investigate the effect of selection against deleterious mutations on the process of inbreeding at a linked neutral locus. Selection was allowed to act within lines only (selection type I) or equally within and between lines (type II). For selfing lines under selection type I, inbreeding is always retarded, the retardation being determined by the recombination fraction between the neutral and selected loci and the inbreeding depression from the selected locus, irrespective of the selection coefficient (s) and dominance coefficient (h) of the mutant allele. For selfing under selection type II or full-sib mating under both selection types, inbreeding is delayed by weak selection (small s and sh), due to the associative overdominance created at the neutral locus, and accelerated by strong selection, due to the elevated differential contributions between alternative alleles at the neutral locus within individuals and between lines (for selection type II). For multiple fitness loci under selection, stochastic simulations were run for populations with selfing, full-sib mating, and random mating, using empirical estimates of mutation parameters and inbreeding load in Drosophila. The simulations results are in general compatible with empirical observations.

APA, Harvard, Vancouver, ISO, and other styles

15

Dranginis, A. M. "Regulation of cell type in yeast by the mating-type locus." Trends in Biochemical Sciences 11, no. 8 (August 1986): 328–31. http://dx.doi.org/10.1016/0968-0004(86)90291-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Bloomfield, Gareth, Jason Skelton, Alasdair Ivens, Yoshimasa Tanaka, and Robert R. Kay. "Sex Determination in the Social Amoeba Dictyostelium discoideum." Science 330, no. 6010 (December 9, 2010): 1533–36. http://dx.doi.org/10.1126/science.1197423.

Full text

Abstract:

The genetics of sex determination remain mysterious in many organisms, including some that are otherwise well studied. Here we report the discovery and analysis of the mating-type locus of the model organism Dictyostelium discoideum. Three forms of a single genetic locus specify this species' three mating types: two versions of the locus are entirely different in sequence, and the third resembles a composite of the other two. Single, unrelated genes are sufficient to determine two of the mating types, whereas homologs of both these genes are required in the composite type. The key genes encode polypeptides that possess no recognizable similarity to established protein families. Sex determination in the social amoebae thus appears to use regulators that are unrelated to any others currently known.

APA, Harvard, Vancouver, ISO, and other styles

17

Klar, Amar J. S. "Regulation of fission yeast mating-type interconversion by chromosome imprinting." Development 108, Supplement (April 1, 1990): 3–8. http://dx.doi.org/10.1242/dev.108.supplement.3.

Full text

Abstract:

Mating types of the fission yeast Schizosaccharomyces pombe interchange nonrandomly in a cell lineage so that only one cell among four granddaughters of a cell ever switches, and the sister of the newly switched cell switches efficiently in consecutive cell divisions, thereby producing chains of recurrent switching. The programme of cellular differentiation is mediated by inheritance of parental DNA chains at the mating type locus (mat1) by progeny cells. This review summarizes recent results suggesting that two types of imprinting events at the mat1 locus are required to generate the specific pattern of switching in a cell lineage. One of those is a site- and strand- specific event that is required before the mat1 locus can be cleaved in vivo. The other is a double-stranded break at mat1 that is healed by gene conversion in the progeny cells resulting in switching the mat1 locus.

APA, Harvard, Vancouver, ISO, and other styles

18

KAWANO, S., T. KUROIWA, and R. W. ANDERSON. "A Third Multiallelic Mating-type Locus in Physarum polycephalum." Microbiology 133, no. 9 (September 1, 1987): 2539–46. http://dx.doi.org/10.1099/00221287-133-9-2539.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Leubner-Metzger, G., B. A. Horwitz, O. C. Yoder, and B. G. Turgeon. "Transcripts at the mating type locus of Cochliobolus heterostrophus." Molecular and General Genetics MGG 256, no. 6 (November 1997): 661–73. http://dx.doi.org/10.1007/s004380050614.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Weiler, K. S., L. Szeto, and J. R. Broach. "Mutations affecting donor preference during mating type interconversion in Saccharomyces cerevisiae." Genetics 139, no. 4 (April 1, 1995): 1495–510. http://dx.doi.org/10.1093/genetics/139.4.1495.

Full text

Abstract:

Abstract Homothallic strains of Saccharomyces cerevisiae can convert mating type from a to alpha or alpha to a as often as every generation, by replacing genetic information specifying one mating type at the expressor locus, MAT, with information specifying the opposite mating type. The cryptic mating type information that is copied and inserted at MAT is contained in either of two loci, HML or HMR. The particular locus selected as donor during mating type interconversion is regulated by the allele expressed at MAT. MATa cells usually select HML, and MAT alpha cells usually select HMR, a process referred to as donor preference. To identify factors required for donor preference, we isolated and characterized a number of mutants that frequently selected the nonpreferred donor locus during mating type interconversion. Many of these mutants were found to harbor chromosome rearrangements or mutations at MAT or HML that interfered with the switching process. However, one mutant carried a recessive allele of CHL1, a gene previously shown to be required for efficient chromosome segregation during mitosis. Homothallic strains of yeast containing a null allele of CHL1 exhibited almost random selection of the donor locus in a MATa background but were normal in their ability to select HMR in a MAT alpha background. Our results indicate that Chl1p participates in the process of donor selection and are consistent with a model in which Chl1p helps establish an intrinsic bias in donor preference.

APA, Harvard, Vancouver, ISO, and other styles

21

Milosevic, Mirjana, Andrés Moya, and Francisco J. Ayala. "Fertility and viability at the Sod locus in Drosophila melanogaster: non-additive and asymmetric selection." Genetical Research 57, no. 3 (June 1991): 267–72. http://dx.doi.org/10.1017/s0016672300029414.

Full text

Abstract:

SummaryExperiments were designed to test in Drosophila melanogaster the effect of mating type at the Sod locus on fertility and viability. The experiments show that fertility is neither additive (or multiplicative) nor symmetric, i.e. that the fertility of a mating type cannot be predicted from the average fertility of the two genotypes involved in the mating. There is no significant male x female interaction with respect or progeny viability; but the interaction is significant for productivity, i.e. when fertility and viability are jointly taken into account. There is overdominance with respect to female fertility, but not with respect to male fertility or to viability. There also is alloprocoptic selection with respect to fertility and with respect to productivity, i.e. matings between like homozygotes are less fertile and productive than matings between dissimilar homozygotes. Selection at the Sod locus yields stable polymorphic equilibria, with the frequency of the F allele predicted at P = 0·641 or 0·695, respectively for low and high larval density.

APA, Harvard, Vancouver, ISO, and other styles

22

Hartmann, Fanny E., Sandra Lorena Ament-Velásquez, Aaron A. Vogan, Valérie Gautier, Stephanie Le Prieur, Myriam Berramdane, Alodie Snirc, et al. "Size Variation of the Nonrecombining Region on the Mating-Type Chromosomes in the Fungal Podospora anserina Species Complex." Molecular Biology and Evolution 38, no. 6 (February 8, 2021): 2475–92. http://dx.doi.org/10.1093/molbev/msab040.

Full text

Abstract:

Abstract Sex chromosomes often carry large nonrecombining regions that can extend progressively over time, generating evolutionary strata of sequence divergence. However, some sex chromosomes display an incomplete suppression of recombination. Large genomic regions without recombination and evolutionary strata have also been documented around fungal mating-type loci, but have been studied in only a few fungal systems. In the model fungus Podospora anserina (Ascomycota, Sordariomycetes), the reference S strain lacks recombination across a 0.8-Mb region around the mating-type locus. The lack of recombination in this region ensures that nuclei of opposite mating types are packaged into a single ascospore (pseudohomothallic lifecycle). We found evidence for a lack of recombination around the mating-type locus in the genomes of ten P. anserina strains and six closely related pseudohomothallic Podospora species. Importantly, the size of the nonrecombining region differed between strains and species, as indicated by the heterozygosity levels around the mating-type locus and experimental selfing. The nonrecombining region is probably labile and polymorphic, differing in size and precise location within and between species, resulting in occasional, but infrequent, recombination at a given base pair. This view is also supported by the low divergence between mating types, and the lack of strong linkage disequilibrium, chromosomal rearrangements, transspecific polymorphism and genomic degeneration. We found a pattern suggestive of evolutionary strata in P. pseudocomata. The observed heterozygosity levels indicate low but nonnull outcrossing rates in nature in these pseudohomothallic fungi. This study adds to our understanding of mating-type chromosome evolution and its relationship to mating systems.

APA, Harvard, Vancouver, ISO, and other styles

23

Leslie, John F., and Carl T. Yamashiro. "Effects of thetolmutation on allelic interactions athetloci inNeurospora crassa." Genome 40, no. 6 (December 1, 1997): 834–40. http://dx.doi.org/10.1139/g97-808.

Full text

Abstract:

A mutant at the tol locus of Neurospora crassa can suppress heterokaryon (vegetative) incompatibility associated with differences at the mating-type locus. We tested the ability of this allele to suppress the vegetative incompatibility reactions that can occur when strains differ at one of nine het loci (het-C, -D, -E, -5, -6, -7, -8, -9, and -10). We found no cases in which the tol mutant suppresses a heteroallelic het locus interaction. Thus, the interaction(s) that leads to vegetative incompatibility because of differences at the mating-type locus is distinct from the interaction(s) that leads to vegetative incompatibility because of differences at any of these nine het loci.Key words: heterokaryon, mating type, vegetative compatibility.

APA, Harvard, Vancouver, ISO, and other styles

24

Vellani, Tia S., Anthony J. F. Griffiths, and N. Louise Glass. "New mutations that suppress mating-type vegetative incompatibility in Neurospora crassa." Genome 37, no. 2 (April 1, 1994): 249–55. http://dx.doi.org/10.1139/g94-035.

Full text

Abstract:

The mating-type locus in the ascomycete Neurospora crassa functions as a vegetative-incompatibility locus during asexual growth such that A + a heterokaryons and A/a partial diploids are inhibited in their growth. In this study, we sought mutations that suppress mating-type associated vegetative incompatibility by using A/a partial diploids. Mutants were selected as spontaneous escapes from inhibited growth. Suppressors were identified by selecting escapes that retained the capacity to mate with both A and a strains. The escaped partial diploids were then outcrossed to remove the duplication. Seven suppressors were identified that segregated as single, recessive mutations. All seven of the suppressors were shown to be allelic to a previously obtained suppressor, tol, by segregation analyses and heterokaryon tests. This result indicates that all seven mutations are new alleles of tol and suggests that tol is a key regulatory locus in the expression of mating-type associated vegetative incompatibility in N. crassa.Key words: vegetative incompatibility, mating type, suppressors, Neurospora.

APA, Harvard, Vancouver, ISO, and other styles

25

Weiler, K. S., and J. R. Broach. "Donor locus selection during Saccharomyces cerevisiae mating type interconversion responds to distant regulatory signals." Genetics 132, no. 4 (December 1, 1992): 929–42. http://dx.doi.org/10.1093/genetics/132.4.929.

Full text

Abstract:

Abstract Mating type interconversion in homothallic strains of the yeast Saccharomyces cerevisiae results from directed transposition of a mating type allele from one of the two silent donor loci, HML and HMR, to the expressing locus, MAT. Cell type regulates the selection of the particular donor locus to be utilized during mating type interconversion: MATa cells preferentially select HML alpha and MAT alpha cells preferentially select HMRa. Such preferential selection indicates that the cell is able to distinguish between HML and HMR during mating type interconversion. Accordingly, we designed experiments to identify those features perceived by the cell to discriminate HML and HMR. We demonstrate that discrimination does not derive from the different structures of the HML and HMR loci, from the unique sequences flanking each donor locus nor from any of the DNA distal to the HM loci on chromosome III. Moreover, we find that the sequences flanking the MAT locus do not function in the preferential selection of one donor locus over the other. We propose that the positions of the donor loci on the left and right arms of chromosome III is the characteristic utilized by the cell to distinguish HML and HMR. This positional information is not generated by either CEN3 or the MAT locus, but probably derives from differences in the chromatin structure, chromosome folding or intranuclear localization of the two ends of chromosome III.

APA, Harvard, Vancouver, ISO, and other styles

26

Bakkeren, Guus, and James W. Kronstad. "The Pheromone Cell Signaling Components of the Ustilago a Mating-Type Loci Determine Intercompatibility Between Species." Genetics 143, no. 4 (August 1, 1996): 1601–13. http://dx.doi.org/10.1093/genetics/143.4.1601.

Full text

Abstract:

Abstract The MAT region of Ustilago hordei, a bipolar barley pathogen, harbors distinct mating functions (a and b loci). Here, we show that the b locus is essential for mating and pathogenicity, and can induce pathogenicity when introduced into a strain carrying a b locus of opposite specificity. Transformation experiments using components of the a1 locus and analysis of resulting dual mating phenotypes revealed that this locus harbors a pheromone receptor gene (Uhpra1) and a pheromone gene (Uhmfa1). These U. hordei a1 genes, when introduced by transformation, are necessary and sufficient to make U. maydis, a tetrapolar corn pathogen, intercompatible with U. hordei MAT-2, but not MAT-1, strains. U. hordei strains transformed with the U. maydis a1 locus also become intercompatible with U. maydis a2, but not a1, strains. The interspecies hybrids produced dikaryotic hyphae but were not fully virulent on either corn or barley. Partial, natural intercompatibility was shown to exist between the sugarcane smut U. scitaminea and both U. hordei and U. maydis. These results show that the signal transduction pathway for mating responses is conserved between different smut species. We conclude that, apart from intraspecies compatibility, the Ustilago a locus also dictates intercompatibility in this group of fungi.

APA, Harvard, Vancouver, ISO, and other styles

27

Karos, M., Y. C. Chang, C. M. McClelland, D. L. Clarke, J. Fu, B. L. Wickes, and K. J. Kwon-Chung. "Mapping of the Cryptococcus neoformans MATα Locus: Presence of Mating Type-Specific Mitogen-Activated Protein Kinase Cascade Homologs." Journal of Bacteriology 182, no. 21 (November 1, 2000): 6222–27. http://dx.doi.org/10.1128/jb.182.21.6222-6227.2000.

Full text

Abstract:

ABSTRACT In this study we investigated the relationship between theMATα locus of Cryptococcus neoformans and several MATα-specific mitogen-activated protein (MAP) kinase signal transduction cascade genes, includingSTE12α, STE11α, and STE20α. To resolve the location of the genes, we screened a cosmid library of the MATα strain B-4500 (JEC21), which was chosen for theC. neoformans genome project. We isolated several overlapping cosmids spanning a region of about 71 kb covering the entire MATα locus. It was found thatSTE12α, STE11α, and STE20α are imbedded within the locus rather than closely linked to the locus. Furthermore, three copies of MFα, the mating type α-pheromone gene, a MATα-specific myosin gene, and a pheromone receptor (CPRα) were identified within the locus. We created a physical map, based on the restriction enzymeBamHI, and identified both borders of theMATα locus. The MATα locus of C. neoformans is approximately 50 kb in size and is one of the largest mating type loci reported among fungi with a one-locus, two-allele mating system.

APA, Harvard, Vancouver, ISO, and other styles

28

Li, Wenjun, Thomas D. Sullivan, Eric Walton, Anna Floyd Averette, Sharadha Sakthikumar, Christina A. Cuomo, Bruce S. Klein, and Joseph Heitman. "Identification of the Mating-Type (MAT) Locus That Controls Sexual Reproduction of Blastomyces dermatitidis." Eukaryotic Cell 12, no. 1 (November 9, 2012): 109–17. http://dx.doi.org/10.1128/ec.00249-12.

Full text

Abstract:

ABSTRACTBlastomyces dermatitidisis a dimorphic fungal pathogen that primarily causes blastomycosis in the midwestern and northern United States and Canada. While the genes controlling sexual development have been known for a long time, the genes controlling sexual reproduction ofB. dermatitidis(teleomorph,Ajellomyces dermatitidis) are unknown. We identified the mating-type (MAT) locus in theB. dermatitidisgenome by comparative genomic approaches. TheB. dermatitidis MATlocus resembles those of other dimorphic fungi, containing either an alpha-box (MAT1-1) or an HMG domain (MAT1-2) gene linked to theAPN2,SLA2, andCOX13genes. However, in some strains ofB. dermatitidis, theMATlocus harbors transposable elements (TEs) that make it unusually large compared to theMATlocus of other dimorphic fungi. Based on theMATlocus sequences ofB. dermatitidis, we designed specific primers for PCR determination of the mating type. TwoB. dermatitidisisolates of opposite mating types were cocultured on mating medium. Immature sexual structures were observed starting at 3 weeks of coculture, with coiled-hyphae-containing cleistothecia developing over the next 3 to 6 weeks. Genetic recombination was detected in potential progeny by mating-type determination, PCR-restriction fragment length polymorphism (PCR-RFLP), and random amplification of polymorphic DNA (RAPD) analyses, suggesting that a meiotic sexual cycle might have been completed. The F1 progeny were sexually fertile when tested with strains of the opposite mating type. Our studies provide a model for the evolution of theMATlocus in the dimorphic and closely related fungi and open the door to classic genetic analysis and studies on the possible roles of mating and mating type in infection and virulence.

APA, Harvard, Vancouver, ISO, and other styles

29

Schirawski, Jan, Bernadette Heinze, Martin Wagenknecht, and Regine Kahmann. "Mating Type Loci of Sporisorium reilianum: Novel Pattern with Three a and Multiple b Specificities." Eukaryotic Cell 4, no. 8 (August 2005): 1317–27. http://dx.doi.org/10.1128/ec.4.8.1317-1327.2005.

Full text

Abstract:

ABSTRACT Sporisorium reilianum and Ustilago maydis are two closely related smut fungi, which both infect maize but differ fundamentally in their mode of plant invasion and site of symptom development. As a prelude to studying the molecular basis of these differences, we have characterized the mating type loci of S. reilianum. S. reilianum has two unlinked mating type loci, a and b. Genes in both loci and adjacent regions show a high degree of synteny to the corresponding genes of U. maydis. The b locus occurs in at least five alleles and encodes two subunits of a heterodimeric homeodomain transcription factor, while the a locus encodes a pheromone/receptor system. However, in contrast to that of U. maydis, the a locus of S. reilianum exists in three alleles containing two active pheromone genes each. The alleles of the a locus appear to have arisen through recent recombination events within the locus itself. This has created a situation where each pheromone is specific for recognition by only one mating partner.

APA, Harvard, Vancouver, ISO, and other styles

30

Klassen, Roland, Daniel Jablonowski, Michael J. R. Stark, Raffael Schaffrath, and Friedhelm Meinhardt. "Mating-type locus control of killer toxins fromKluyveromyces lactisandPichia acaciae." FEMS Yeast Research 6, no. 3 (May 2006): 404–13. http://dx.doi.org/10.1111/j.1567-1364.2005.00006.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Cogliati, Massimo, Maria Carmela Esposto, Anna Maria Tortorano, and Maria Anna Viviani. "Cryptococcus neoformanspopulation includes hybrid strains homozygous at mating-type locus." FEMS Yeast Research 6, no. 4 (June 2006): 608–13. http://dx.doi.org/10.1111/j.1567-1364.2006.00085.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Ferris, Patrick J., E. Virginia Armbrust, and Ursula W. Goodenough. "Genetic Structure of the Mating-Type Locus of Chlamydomonas reinhardtii." Genetics 160, no. 1 (January 1, 2002): 181–200. http://dx.doi.org/10.1093/genetics/160.1.181.

Full text

Abstract:

Abstract Portions of the cloned mating-type (MT) loci (mt+ and mt−) of Chlamydomonas reinhardtii, defined as the ~1-Mb domains of linkage group VI that are under recombinational suppression, were subjected to Northern analysis to elucidate their coding capacity. The four central rearranged segments of the loci were found to contain both housekeeping genes (expressed during several life-cycle stages) and mating-related genes, while the sequences unique to mt+ or mt− carried genes expressed only in the gametic or zygotic phases of the life cycle. One of these genes, Mtd1, is a candidate participant in gametic cell fusion; two others, Mta1 and Ezy2, are candidate participants in the uniparental inheritance of chloroplast DNA. The identified housekeeping genes include Pdk, encoding pyruvate dehydrogenase kinase, and GdcH, encoding glycine decarboxylase complex subunit H. Unusual genetic configurations include three genes whose sequences overlap, one gene that has inserted into the coding region of another, several genes that have been inactivated by rearrangements in the region, and genes that have undergone tandem duplication. This report extends our original conclusion that the MT locus has incurred high levels of mutational change.

APA, Harvard, Vancouver, ISO, and other styles

33

Li, Wenjun, Banu Metin, Theodore C. White, and Joseph Heitman. "Organization and Evolutionary Trajectory of the Mating Type (MAT) Locus in Dermatophyte and Dimorphic Fungal Pathogens." Eukaryotic Cell 9, no. 1 (October 30, 2009): 46–58. http://dx.doi.org/10.1128/ec.00259-09.

Full text

Abstract:

ABSTRACT Sexual reproduction in fungi is governed by a specialized genomic region, the mating type (MAT) locus, whose gene identity, organization, and complexity are diverse. We identified the MAT locus of five dermatophyte fungal pathogens (Microsporum gypseum, Microsporum canis, Trichophyton equinum, Trichophyton rubrum, and Trichophyton tonsurans) and a dimorphic fungus, Paracoccidioides brasiliensis, and performed phylogenetic analyses. The identified MAT locus idiomorphs of M. gypseum control cell type identity in mating assays, and recombinant progeny were produced. Virulence tests in Galleria mellonella larvae suggest the two mating types of M. gypseum may have equivalent virulence. Synteny analysis revealed common features of the MAT locus shared among these five dermatophytes: namely, a small size (∼3 kb) and a novel gene arrangement. The SLA2, COX13, and APN2 genes, which flank the MAT locus in other Ascomycota are instead linked on one side of the dermatophyte MAT locus. In addition, the transcriptional orientations of the APN2 and COX13 genes are reversed compared to the dimorphic fungi Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii. A putative transposable element, pogo, was found to have inserted in the MAT1-2 idiomorph of one P. brasiliensis strain but not others. In conclusion, the evolution of the MAT locus of the dermatophytes and dimorphic fungi from the last common ancestor has been punctuated by both gene acquisition and expansion, and asymmetric gene loss. These studies further support a foundation to develop molecular and genetic tools for dermatophyte and dimorphic human fungal pathogens.

APA, Harvard, Vancouver, ISO, and other styles

34

Thon, G., and A. J. Klar. "The clr1 locus regulates the expression of the cryptic mating-type loci of fission yeast." Genetics 131, no. 2 (June 1, 1992): 287–96. http://dx.doi.org/10.1093/genetics/131.2.287.

Full text

Abstract:

Abstract The mat2-P and mat3-M loci of fission yeast contain respectively the plus (P) and minus (M) mating-type information in a transcriptionally silent state. That information is transposed from the mat2 or mat3 donor locus via recombination into the expressed mating-type locus (mat1) resulting in switching of the cellular mating type. We have identified a gene, named clr1 (for cryptic loci regulator), whose mutations allow expression of the mat2 and mat3 loci. clr1 mutants undergo aberrant haploid meiosis, indicative of transcription of the silent genes. Production of mRNA from mat3 is detectable in clr1 mutants. Furthermore, the ura4 gene inserted near mat3, weakly expressed in wild-type cells, is derepressed in clr1 mutants. The clr1 mutations also permit meiotic recombination in the 15-kb mat2-mat3 interval, where recombination is normally inhibited. The clr1 locus is in the right arm of chromosome II. We suggest that clr1 regulates silencing of the mat2 and mat3 loci, and participates in establishing the "cold spot" for recombination by organizing the chromatin structure of the mating-type region.

APA, Harvard, Vancouver, ISO, and other styles

35

Pöggeler, Stefanie, Siegfried Risch, Ulrich Kück, and Heinz D. Osiewacz. "Mating-Type Genes From the Homothallic Fungus Sordaria macrospora Are Functionally Expressed in a Heterothallic Ascomycete." Genetics 147, no. 2 (October 1, 1997): 567–80. http://dx.doi.org/10.1093/genetics/147.2.567.

Full text

Abstract:

Homokaryons from the homothallic ascomycte Sordaria macrospora are able to enter the sexual pathway and to form fertile fruiting bodies. To analyze the molecular basis of homothallism and to elucidate the role of mating-products during fruiting body development, we cloned and sequenced the entire S. macrospora mating-type locus. Comparison of the Sordaria mating-type locus with mating-type idiomorphs from the heterothallic ascomycetes Neurospora crassa and Podospora anserina revealed that sequences from both idiomorphs (A/a and mat–/mat+, respectively) are contiguous in S. macrospora. DNA sequencing of the S. macrospora mating-type region allowed the identification of four open reading frames (ORFs), which were termed Smt-a1, SmtA-1, SmtA-2 and SmtA-3. While Smt-a1, SmtA-1, and SmtA-2 show strong sequence similarities with the corresponding N. crassa mating-type ORFs, SmtA-3 has a chimeric character. It comprises sequences that are similar to the A and a mating-type idiomorph from N. crassa. To determine functionality of the S. macrospora mating-type genes, we show that all ORFs are transcriptionally expressed. Furthermore, we transformed the S. macrospora mating-type genes into mat– and mat+ strains of the closely related heterothallic fungus P. anserina. The transformation experiments show that mating-type genes from S. macrospora induce fruiting body formation in P. anserina.

APA, Harvard, Vancouver, ISO, and other styles

36

Halliday, C. L., T. Bui, M. Krockenberger, R. Malik, D. H. Ellis, and D. A. Carter. "Presence of α and a Mating Types in Environmental and Clinical Collections of Cryptococcus neoformans var. gattii Strains from Australia." Journal of Clinical Microbiology 37, no. 9 (1999): 2920–26. http://dx.doi.org/10.1128/jcm.37.9.2920-2926.1999.

Full text

Abstract:

Cryptococcus neoformans var. gattii lives in association with certain species of eucalyptus trees and is a causative agent of cryptococcosis. It exists as two mating types, MATα and MATa, which is determined by a single-locus, two-allele system. In the closely related C. neoformansvar. neoformans, the α mating type has been found to outnumber its a counterpart by at least 30:1, but there have been very limited data on the proportions of each mating type in C. neoformans var. gattii. In the present study, specific PCR primers were designed to amplify two separate α-mating-type genes from C. neoformans var.gattii strains. These were used to survey for the presence of the two mating types in clinical and environmental collections ofC. neoformans var. gattii strains from Australia. Sixty-eight of 69 clinical isolates produced both α mating type-specific bands and were assumed to be of the α mating type. The majority of environmental isolates were also of the α mating type, but the a mating type was located in two separate areas. In one area, the a mating type outnumbered the α mating type by 27:2, but in the second area, the ratio of the two mating types was close to the 50:50 ratio expected for sexual recombination.

APA, Harvard, Vancouver, ISO, and other styles

37

Li, J. Q., B. D. Wingfield, M. J. Wingfield, I. Barnes, A. Fourie, P. W. Crous, and S. F. Chen. "Mating genes in Calonectria and evidence for a heterothallic ancestral state." Persoonia - Molecular Phylogeny and Evolution of Fungi 45, no. 1 (December 31, 2020): 163–76. http://dx.doi.org/10.3767/persoonia.2020.45.06.

Full text

Abstract:

The genus Calonectria includes many important plant pathogens with a wide global distribution. In order to better understand the reproductive biology of these fungi, we characterised the structure of the mating type locus and flanking genes using the genome sequences for seven Calonectria species. Primers to amplify the mating type genes in other species were also developed. PCR amplification of the mating type genes and multi-gene phylogenetic analyses were used to investigate the mating strategies and evolution of mating type in a collection of 70 Calonectria species residing in 10 Calonectria species complexes. Results showed that the organisation of the MAT locus and flanking genes is conserved. In heterothallic species, a novel MAT gene, MAT1-2-12 was identified in the MAT1-2 idiomorph;the MAT1-1 idiomorph, in most cases, contained the MAT1-1-3 gene. Neither MAT1-1-3 nor MAT1-2-12 was found in homothallic Calonectria (Ca.) hongkongensis, Ca. lateralis, Ca. pseudoturangicola and Ca. turangicola. Four different homothallic MAT locus gene arrangements were observed. Ancestral state reconstruction analysis provided evidence that the homothallic state was basal in Calonectria and this evolved from a heterothallic ancestor.

APA, Harvard, Vancouver, ISO, and other styles

38

Fraser, James A., Jason E. Stajich, Eric J. Tarcha, Garry T. Cole, Diane O. Inglis, Anita Sil, and Joseph Heitman. "Evolution of the Mating Type Locus: Insights Gained from the Dimorphic Primary Fungal Pathogens Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii." Eukaryotic Cell 6, no. 4 (March 2, 2007): 622–29. http://dx.doi.org/10.1128/ec.00018-07.

Full text

Abstract:

ABSTRACT Sexual reproduction of fungi is governed by the mating type (MAT) locus, a specialized region of the genome encoding key transcriptional regulators that direct regulatory networks to specify cell identity and fate. Knowledge of MAT locus structure and evolution has been considerably advanced in recent years as a result of genomic analyses that enable the definition of MAT locus sequences in many species as well as provide an understanding of the evolutionary plasticity of this unique region of the genome. Here, we extend this analysis to define the mating type locus of three dimorphic primary human fungal pathogens, Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii, using genomic analysis, direct sequencing, and bioinformatics. These studies provide evidence that all three species possess heterothallic bipolar mating type systems, with isolates encoding either a high-mobility-group (HMG) domain or an α-box transcriptional regulator. These genes are intact in all loci examined and have not been subject to loss or decay, providing evidence that the loss of fertility upon passage in H. capsulatum is not attributable to mutations at the MAT locus. These findings also suggest that an extant sexual cycle remains to be defined in both Coccidioides species, in accord with population genetic evidence. Based on these MAT sequences, a facile PCR test was developed that allows the mating type to be rapidly ascertained. Finally, these studies highlight the evolutionary forces shaping the MAT locus, revealing examples in which flanking genes have been inverted or subsumed and incorporated into an expanding MAT locus, allowing us to propose an expanded model for the evolution of the MAT locus in the phylum Ascomycota.

APA, Harvard, Vancouver, ISO, and other styles

39

Soll, David R. "Mating-type locus homozygosis, phenotypic switching and mating: a unique sequence of dependencies inCandida albicans." BioEssays 26, no. 1 (2003): 10–20. http://dx.doi.org/10.1002/bies.10379.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Bystricky, Kerstin, Haico Van Attikum, Maria-Dolores Montiel, Vincent Dion, Lutz Gehlen, and Susan M. Gasser. "Regulation of Nuclear Positioning and Dynamics of the Silent Mating Type Loci by the Yeast Ku70/Ku80 Complex." Molecular and Cellular Biology 29, no. 3 (December 1, 2008): 835–48. http://dx.doi.org/10.1128/mcb.01009-08.

Full text

Abstract:

ABSTRACT We have examined the hypothesis that the highly selective recombination of an active mating type locus (MAT) with either HMLα or HMR a is facilitated by the spatial positioning of relevant sequences within the budding yeast (Saccharomyces cerevisiae) nucleus. However, both position relative to the nuclear envelope (NE) and the subnuclear mobility of fluorescently tagged MAT, HML, or HMR loci are largely identical in haploid a and α cells. Irrespective of mating type, the expressed MAT locus is highly mobile within the nuclear lumen, while silent loci move less and are found preferentially near the NE. The perinuclear positions of HMR and HML are strongly compromised in strains lacking the Silent information regulator, Sir4. However, HMLα, unlike HMR a and most telomeres, shows increased NE association in a strain lacking yeast Ku70 (yKu70). Intriguingly, we find that the yKu complex is associated with HML and HMR sequences in a mating-type-specific manner. Its abundance decreases at the HMLα donor locus and increases transiently at MAT a following DSB induction. Our data suggest that mating-type-specific binding of yKu to HMLα creates a local chromatin structure competent for recombination, which cooperates with the recombination enhancer to direct donor choice for gene conversion of the MAT a locus.

APA, Harvard, Vancouver, ISO, and other styles

41

Lengeler, Klaus B., Gary M. Cox, and Joseph Heitman. "Serotype AD Strains of Cryptococcus neoformans Are Diploid or Aneuploid and Are Heterozygous at the Mating-Type Locus." Infection and Immunity 69, no. 1 (January 1, 2001): 115–22. http://dx.doi.org/10.1128/iai.69.1.115-122.2001.

Full text

Abstract:

ABSTRACT Cryptococcus neoformans is a pathogenic basidiomycete with a defined sexual cycle involving mating between haploid yeast cells with a transient diploid state. C. neoformans occurs in four predominant serotypes (A, B, C, and D), which represent different varieties or species. Rare clinical and environmental isolates with an unusual AD serotype have been reported and suggested to be diploid. We found by fluorescence-activated cell sorter analysis that serotype AD strains are aneuploid or diploid. PCR analysis with primers specific for serotype A or D alleles of theCNA1, CLA4, and GPA1 genes revealed that both alleles are often present in serotype AD strains. PCR analysis with primers specific for genes in the MATa orMATα mating-type loci revealed that serotype AD strains are heterozygous for the mating-type locus. Interestingly, in several serotype AD strains, the MATα locus was derived from the serotype D parent and the MATa locus was inherited from a serotype A parent that has been thought to be extinct. Basidiospores from a self-fertile serotype AD strain bearing the putative serotype AMATa locus showed a very low viability (∼5%), and no fertile serotype A MATa strain could be recovered. Serotype AD strains were virulent in a murine model. Hybrid AD strains could readily be isolated following a laboratory cross between a serotype A strain and a serotype D strain. In summary, serotype AD strains ofC. neoformans are unusual aneuploid or diploid strains that result from matings between serotype A and D strains. Self-fertile isolates fail to undergo normal meiosis because of genetic divergence. Our findings further suggest that serotype A MATa strains may exist in nature.

APA, Harvard, Vancouver, ISO, and other styles

42

Yan, Zhun, and Jianping Xu. "Mitochondria Are Inherited From the MATa Parent in Crosses of the Basidiomycete Fungus Cryptococcus neoformans." Genetics 163, no. 4 (April 1, 2003): 1315–25. http://dx.doi.org/10.1093/genetics/163.4.1315.

Full text

Abstract:

Abstract Previous studies demonstrated that mitochondrial DNA (mtDNA) was uniparentally transmitted in laboratory crosses of the pathogenic yeast Cryptococcus neoformans. To begin understanding the mechanisms, this study examined the potential role of the mating-type locus on mtDNA inheritance in C. neoformans. Using existing isogenic strains (JEC20 and JEC21) that differed only at the mating-type locus and a clinical strain (CDC46) that possessed a mitochondrial genotype different from JEC20 and JEC21, we constructed strains that differed only in mating type and mitochondrial genotype. These strains were then crossed to produce hyphae and sexual spores. Among the 206 single spores analyzed from six crosses, all but one inherited mtDNA from the MATa parents. Analyses of mating-type alleles and mtDNA genotypes of natural hybrids from clinical and natural samples were consistent with the hypothesis that mtDNA is inherited from the MATa parent in C. neoformans. To distinguish two potential mechanisms, we obtained a pair of isogenic strains with different mating-type alleles, mtDNA types, and auxotrophic markers. Diploid cells from mating between these two strains were selected and 29 independent colonies were genotyped. These cells did not go through the hyphal stage or the meiotic process. All 29 colonies contained mtDNA from the MATa parent. Because no filamentation, meiosis, or spore formation was involved in generating these diploid cells, our results suggest a selective elimination of mtDNA from the MATα parent soon after mating. To our knowledge, this is the first demonstration that mating type controls mtDNA inheritance in fungi.

APA, Harvard, Vancouver, ISO, and other styles

43

Pardo, Eneida H., Suzanne F. O'Shea, and Lorna A. Casselton. "Multiple Versions of the A Mating Type Locus of Coprinus cinereus are Generated by Three Paralogous Pairs of Multiallelic Homeobox Genes." Genetics 144, no. 1 (September 1, 1996): 87–94. http://dx.doi.org/10.1093/genetics/144.1.87.

Full text

Abstract:

Abstract The A mating type locus of Coprinus cinereus determines mating compatibility by regulating essential steps in sexual development. Each A locus contains several genes separated into two functionally independent complexes termed Aα and Aβ, and the multiple alleles of these genes generate an estimated 160 A mating specificities. The genes encode two classes of homeodomain-containing proteins designated HD1 and HD2. In this report we describe two newly cloned loci, A2 and A5, and compare them with A42, A43 and A6 that we have described previously. An Aβ-null locus, retaining just a single active HD1 gene from the α-complex, was generated by mutation. Using this as a transformation host, gene combinations that promote A-regulated development were identified. We demonstrate that each A locus contains members of three paralogous pairs of HD1 and HD2 genes. Different allelic versions of gene pairs are compatible but paralogous genes are incompatible. The genes present in four uncloned A loci were deduced using Southern analyses and transformations with available cloned genes. The combined analysis of nine A factors identifies sufficient A gene alleles to generate at least 72 A mating specificities.

APA, Harvard, Vancouver, ISO, and other styles

44

Galloway, R. E., and U. W. Goodenough. "GENETIC ANALYSIS OF MATING LOCUS LINKED MUTATIONS IN CHLAMYDOMONAS REINHARDII." Genetics 111, no. 3 (November 1, 1985): 447–61. http://dx.doi.org/10.1093/genetics/111.3.447.

Full text

Abstract:

ABSTRACT The mating-type (mt) locus of Chlamydomonas reinhardii has been analyzed using four mutant strains (imp-1, imp-10, imp-11 and imp-12). All have been shown, or are shown here, to carry mutations linked to either the plus (mt +) or the minus (mt -) locus, and their behavior in complementation tests has allowed us to define several distinct functions for each locus. Specifically, we propose that the mt + locus contains the following genes or regulatory elements: a locus designated sfu, which is necessary for sexual fusion between gametes; a locus designated upp (uniparental plus), which controls aspects of chloroplast gene inheritance and perhaps also zygote maturation; and a locus designated sad, which functions in sexual adhesion. The mt - locus also contains a sad locus as well as a gene or regulatory element designated mid, which is necessary for the minus dominance in mt +/mt - diploids.

APA, Harvard, Vancouver, ISO, and other styles

45

Srikantha, Thyagarajan, Salil A. Lachke, and David R. Soll. "Three Mating Type-Like Loci in Candida glabrata." Eukaryotic Cell 2, no. 2 (April 2003): 328–40. http://dx.doi.org/10.1128/ec.2.2.328-340.2003.

Full text

Abstract:

ABSTRACT Candida glabrata, the second most prevalent Candida species colonizing humans, possesses three mating type-like (MTL) loci (MTL1, MTL2, and MTL3). These loci contain pairs of MTL genes with their respective coding regions on complementary Crick and Watson DNA strands. Each pair of genes is separated by a shared intergenic promoter region, the same configuration found at the mating type loci of Saccharomyces cerevisiae. Two of the MTL loci, MTL1 and MTL2, contain either the MTLa1/MTLa2 configuration or the MTLα1/MTLα2 configuration in different strains. All but one of the 38 tested C. glabrata strains were either aaα or aαα. One test strain was ααα. Based on the mating type genotype, the MTL genes at the MTL1 or MTL2 loci, and the size of the XbaI fragment harboring MTL1 or MTL2, four classes of C. glabrata strains (I, II, III, and IV) were distinguished. Northern analysis revealed that strains were either a-expressors or α-expressors and that expression always reflected the genotype of either the MTL1 or MTL2 locus, depending on the class. The expression pattern in each class, therefore, is similar to that observed in S. cerevisiae, which harbors two silent cassette loci, HMR and HML, and the expression locus MAT. High-frequency phenotypic switching between core phenotypes in an α-expressing, but not in an a-expressing, strain modulated the level of MTL expression, suggesting a possible relationship between core phenotypic switching and mating.

APA, Harvard, Vancouver, ISO, and other styles

46

Larraya, Luis M., Gúmer Pérez, Iñaki Iribarren, Juan A. Blanco, Mikel Alfonso, Antonio G. Pisabarro, and Lucı́a Ramı́rez. "Relationship between Monokaryotic Growth Rate and Mating Type in the Edible Basidiomycete Pleurotus ostreatus." Applied and Environmental Microbiology 67, no. 8 (August 1, 2001): 3385–90. http://dx.doi.org/10.1128/aem.67.8.3385-3390.2001.

Full text

Abstract:

ABSTRACT The edible fungus Pleurotus ostreatus (oyster mushroom) is an industrially produced heterothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Two mating loci (matA and matB) control different steps of hyphal fusion, nuclear migration, and nuclear sorting during the onset and progress of the dikaryotic growth. Previous studies have shown that the segregation of the alleles present at thematB locus differs from that expected for a single locus because (i) new nonparental B alleles appeared in the progeny and (ii) there was a distortion in the segregation of the genomic regions close to this mating locus. In this study, we pursued these observations by using a genetic approach based on the identification of molecular markers linked to the matBlocus that allowed us to dissect it into two genetically linked subunits (matBα and matBβ) and to correlate the presence of specific matBα and matAalleles with differences in monokaryotic growth rate. The availability of these molecular markers and the mating type dependence of growth rate in monokaryons can be helpful for marker-assisted selection of fast-growing monokaryons to be used in the construction of dikaryons able to colonize the substrate faster than the competitors responsible for reductions in the industrial yield of this fungus.

APA, Harvard, Vancouver, ISO, and other styles

47

Ravindra, Anish, Kerstin Weiss, and Robert T. Simpson. "High-Resolution Structural Analysis of Chromatin at Specific Loci: Saccharomyces cerevisiae Silent Mating-Type Locus HMRa." Molecular and Cellular Biology 19, no. 12 (December 1, 1999): 7944–50. http://dx.doi.org/10.1128/mcb.19.12.7944.

Full text

Abstract:

ABSTRACT Genetic and biochemical evidence implicates chromatin structure in the silencing of the two quiescent mating-type loci near the telomeres of chromosome III in yeast. With high-resolution micrococcal nuclease mapping, we show that the HMRa locus has 12 precisely positioned nucleosomes spanning the distance between the E and I silencer elements. The nucleosomes are arranged in pairs with very short linkers; the pairs are separated from one another by longer linkers of ∼20 bp. Both the basic amino-terminal region of histone H4 and the silent information regulator protein Sir3p are necessary for the organized repressive chromatin structure of the silent locus. Compared to HMRa, only small differences in the availability of the TATA box are present for the promoter in the cassette at the active MATa locus. Features of the chromatin structure of this silent locus compared to the previously studied HMLα locus suggest differences in the mechanisms of silencing and may relate to donor selection during mating-type interconversion.

APA, Harvard, Vancouver, ISO, and other styles

48

Wang, Ping, Connie B. Nichols, Klaus B. Lengeler, Maria E. Cardenas, Gary M. Cox, John R. Perfect, and Joseph Heitman. "Mating-Type-Specific and Nonspecific PAK Kinases Play Shared and Divergent Roles in Cryptococcus neoformans." Eukaryotic Cell 1, no. 2 (April 2002): 257–72. http://dx.doi.org/10.1128/ec.1.2.257-272.2002.

Full text

Abstract:

ABSTRACT Cryptococcus neoformans is an opportunistic fungal pathogen with a defined sexual cycle involving fusion of haploid MATα and MATa cells. Virulence has been linked to the mating type, and MATα cells are more virulent than congenic MATa cells. To study the link between the mating type and virulence, we functionally analyzed three genes encoding homologs of the p21-activated protein kinase family: STE20α, STE20a, and PAK1. In contrast to the STE20 genes that were previously shown to be in the mating-type locus, the PAK1 gene is unlinked to the mating type. The STE20α, STE20a, and PAK1 genes were disrupted in serotype A and D strains of C. neoformans, revealing central but distinct roles in mating, differentiation, cytokinesis, and virulence. ste20α pak1 and ste20a pak1 double mutants were synthetically lethal, indicating that these related kinases share an essential function. In summary, our studies identify an association between the STE20α gene, the MATα locus, and virulence in a serotype A clinical isolate and provide evidence that PAK kinases function in a MAP kinase signaling cascade controlling the mating, differentiation, and virulence of this fungal pathogen.

APA, Harvard, Vancouver, ISO, and other styles

49

Lockhart, Shawn R., Claude Pujol, Karla J. Daniels, Matthew G. Miller, Alexander D. Johnson, Michael A. Pfaller, and David R. Soll. "In Candida albicans, White-Opaque Switchers Are Homozygous for Mating Type." Genetics 162, no. 2 (October 1, 2002): 737–45. http://dx.doi.org/10.1093/genetics/162.2.737.

Full text

Abstract:

Abstract The relationship between the configuration of the mating type locus (MTL) and white-opaque switching in Candida albicans has been examined. Seven genetically unrelated clinical isolates selected for their capacity to undergo the white-opaque transition all proved to be homozygous at the MTL locus, either MTLa or MTLα. In an analysis of the allelism of 220 clinical isolates representing the five major clades of C. albicans, 3.2% were homozygous and 96.8% were heterozygous at the MTL locus. Of the seven identified MTL homozygotes, five underwent the white-opaque transition. Of 20 randomly selected MTL heterozygotes, 18 did not undergo the white-opaque transition. The two that did were found to become MTL homozygous at very high frequency before undergoing white-opaque switching. Our results demonstrate that only MTL homozygotes undergo the white-opaque transition, that MTL heterozygotes that become homozygous at high frequency exist, and that the generation of MTL homozygotes and the white-opaque transition occur in isolates in different genetic clades of C. albicans. Our results demonstrate that mating-competent strains of C. albicans exist naturally in patient populations and suggest that mating may play a role in the genesis of diversity in this pernicious fungal pathogen.

APA, Harvard, Vancouver, ISO, and other styles

50

Shiu, Patrick Ka Tai, and N. Louise Glass. "Molecular Characterization of tol, a Mediator of Mating-Type-Associated Vegetative Incompatibility in Neurospora crassa." Genetics 151, no. 2 (February 1, 1999): 545–55. http://dx.doi.org/10.1093/genetics/151.2.545.

Full text

Abstract:

Abstract The mating-type locus in the haploid filamentous fungus, Neurospora crassa, controls mating and sexual development. The fusion of reproductive structures of opposite mating type, A and a, is required to initiate sexual reproduction. However, the fusion of hyphae of opposite mating type during vegetative growth results in growth inhibition and cell death, a process that is mediated by the tol locus. Mutations in tol are recessive and suppress mating-type-associated heterokaryon incompatibility. In this study, we describe the cloning and characterization of tol. The tol gene encodes a putative 1011-amino-acid polypeptide with a coiled-coil domain and a leucine-rich repeat. Both regions are required for tol activity. Repeat-induced point mutations in tol result in mutants that are wild type during vegetative growth and sexual reproduction, but that allow opposite mating-type individuals to form a vigorous heterokaryon. Transcript analyses show that tol mRNA is present during vegetative growth but absent during a cross. These data suggest that tol transcription is repressed to allow the coexistence of opposite mating-type nuclei during the sexual reproductive phase. tol is expressed in a mat A, mat a, A/a partial diploid and in a mating-type deletion strain, indicating that MAT A-1 and MAT a-1 are not absolutely required for transcription or repression of tol. These data suggest that TOL may rather interact with MAT A-1 and/or MAT a-1 (or downstream products) to form a death-triggering complex.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Mating type locus'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles