scholarly journals Schizosaccharomyces pombe ras1 and byr1 are functionally related genes of the ste family that affect starvation-induced transcription of mating-type genes.

1990 ◽  
Vol 10 (2) ◽  
pp. 549-560 ◽  
Author(s):  
S A Nadin-Davis ◽  
A Nasim
Keyword(s):  
Gene Family ◽  
Fission Yeast ◽  
Mating Type ◽  
Growth Cycle ◽  
Yeast Cells ◽  
Null Alleles ◽  
Northern Analysis ◽  
Gene Transcript ◽  
Type Gene

We have further investigated the function of the ras1 and byr1 genes, which were previously shown to be critical for sexual differentiation in fission yeast cells. Several physiological similarities between strains containing null alleles of these genes supports the idea that ras1 and byr1 are functionally closely related. Furthermore, we have found that byr1 is allelic to ste1, one of at least 10 genes which when mutated can cause sterility. Since ras1 had previously been found to be allelic to ste5, both ras and byr genes are now clearly shown to be a part of the ste gene family, thus confirming their close functional relationship. The observation that the mating-type loci could overcome the sporulation block of ras1 and byr1 mutant strains prompted investigation of the role of the ras-byr pathway in the induction of the mating-type gene transcripts upon nitrogen starvation. By Northern analysis of RNA preparations from strains carrying wild-type or mutant ras1 alleles and grown to different stages of the growth cycle, we have shown that ras1 plays an important role in inducing the Pi transcript of the mating-type loci and the mei3 gene transcript. These observations provide a molecular basis for the role of the ste gene family, including ras1 and byr1, in meiosis and indicate that further characterization of other ste genes would be very useful for elucidating the mechanism of ras1 function in fission yeast cells.

Schizosaccharomyces pombe ras1 and byr1 are functionally related genes of the ste family that affect starvation-induced transcription of mating-type genes

1990 ◽  
Vol 10 (2) ◽  
pp. 549-560
Author(s):  
S A Nadin-Davis ◽  
A Nasim
Keyword(s):  
Gene Family ◽  
Fission Yeast ◽  
Mating Type ◽  
Growth Cycle ◽  
Yeast Cells ◽  
Null Alleles ◽  
Northern Analysis ◽  
Gene Transcript ◽  
Type Gene

We have further investigated the function of the ras1 and byr1 genes, which were previously shown to be critical for sexual differentiation in fission yeast cells. Several physiological similarities between strains containing null alleles of these genes supports the idea that ras1 and byr1 are functionally closely related. Furthermore, we have found that byr1 is allelic to ste1, one of at least 10 genes which when mutated can cause sterility. Since ras1 had previously been found to be allelic to ste5, both ras and byr genes are now clearly shown to be a part of the ste gene family, thus confirming their close functional relationship. The observation that the mating-type loci could overcome the sporulation block of ras1 and byr1 mutant strains prompted investigation of the role of the ras-byr pathway in the induction of the mating-type gene transcripts upon nitrogen starvation. By Northern analysis of RNA preparations from strains carrying wild-type or mutant ras1 alleles and grown to different stages of the growth cycle, we have shown that ras1 plays an important role in inducing the Pi transcript of the mating-type loci and the mei3 gene transcript. These observations provide a molecular basis for the role of the ste gene family, including ras1 and byr1, in meiosis and indicate that further characterization of other ste genes would be very useful for elucidating the mechanism of ras1 function in fission yeast cells.

The role of recombinational repair proteins in mating type switching in fission yeast cells

2006 ◽  
Vol 42 (4) ◽  
pp. 385-391 ◽  
Author(s):  
D. A. Vagin ◽  
F. K. Khasanov ◽  
V. I. Bashkirov
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Yeast Cells ◽  
Recombinational Repair ◽  
Mating Type Switching

scholarly journals Deletion of the Schizophyllum commune Aα Locus: The Roles of Aα Y and Z Mating-Type Genes

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1437-1444
Author(s):  
C Ian Robertson ◽  
Kirk A Bartholomew ◽  
Charles P Novotny ◽  
Robert C Ullrich
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Mating Types ◽  
Developmental Pathway ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Regulatory Loci ◽  
Type Gene

The Aα locus is one of four master regulatory loci that determine mating type and regulate sexual development in Schizophyllum commune. We have made a plasmid containing a URA1 gene disruption of the Aα Y1 gene. Y1 is the sole Aα gene in Aα1 strains. We used the plasmid construction to produce an Aα null (i.e., AαΔ) strain by replacing the genomic Y1 gene with URA1 in an Aα1 strain. To characterize the role of the Aα genes in the regulation of sexual development, we transformed various Aα Y and Z alleles into AαΔ strains and examined the acquired mating types and mating abilities of the transformants. These experiments demonstrate that the Aα Y gene is not essential for fungal viability and growth, that a solitary Z Aα mating-type gene does not itself activate development, that Aβ proteins are sufficient to activate the A developmental pathway in the absence of Aα proteins and confirm that Y and Z genes are the sole determinants of Aα mating type. The data from these experiments support and refine our model of the regulation of A-pathway events by Y and Z proteins.

scholarly journals The size-wise nucleus: nuclear volume control in eukaryotes

2007 ◽  
Vol 179 (4) ◽  
pp. 583-584 ◽  
Author(s):  
Michael D. Huber ◽  
Larry Gerace
Keyword(s):  
Fission Yeast ◽  
Cell Size ◽  
Size Control ◽  
Growth Conditions ◽  
Nuclear Size ◽  
Yeast Cells ◽  
Volume Control ◽  
Wide Range ◽  
The Relationship

Eukaryotic cells have an “awareness” of their volume and organellar volumes, and maintain a nuclear size that is proportional to the total cell size. New studies in budding and fission yeast have examined the relationship between cell and nuclear volumes. It was found that the size of the nucleus remains proportional to cell size in a wide range of genetic backgrounds and growth conditions that alter cell volume and DNA content. Moreover, in multinucleated fission yeast cells, Neumann and Nurse (see p. 593 of this issue) found that the sizes of individual nuclei are controlled by the relative amount of cytoplasm surrounding each nucleus. These results highlight a role of the cytoplasm in nuclear size control.

scholarly journals A Recombinationally Repressed Region Between mat2 and mat3 Loci Shares Homology to Centromeric Repeats and Regulates Directionality of Mating-Type Switching in Fission Yeast

Genetics ◽  
1997 ◽  
Vol 146 (4) ◽  
pp. 1221-1238 ◽  
Author(s):  
Shiv I S Grewal ◽  
Amar J S Klar
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Sequencing Analysis ◽  
Cell Type ◽  
Cloning And Sequencing ◽  
Type Region ◽  
Repeat Sequences ◽  
Mating Type Switching ◽  
Cell Type Specific

Cells of the fission yeast Schizosaccharomyces pombe switch mating type by replacing genetic information at the transcriptionally active mat1 locus with sequences copied from one of two closely linked silent loci, mat2-P or mat3-M. By a process referred to as directionality of switching, cells predominantly switch to the opposite mat1 allele; the mat1-P allele preferentially recombines with mat3, while mat1-M selects the mat2. In contrast to efficient recombination at mat1, recombination within the adjoining mat2-mat3 interval is undetectable. We defined the role of sequences between mat2 and mat3, designated the K-region, in directionality as well as recombinational suppression. Cloning and sequencing analysis revealed that a part of the K-region is homologous to repeat sequences present at centromeres, which also display transcriptional and recombinational suppression. Replacement of 7.5 kb of the K-region with the ura4  + gene affected directionality in a variegated manner. Analysis of the swi6-mod locus, which was previously shown to affect directionality, in KΔ::ura4  + strains suggested the existence of at least two overlapping directionality mechanisms. Our work furthers the model that directionality is regulated by cell-type-specific organization of the heterochromatin-like structure in the mating-type region and provides evidence that the K-region contributes to silencing of the mat2-mat3 interval.

scholarly journals Mating-Type Gene Structure and Spatial Distribution of Didymella tanaceti in Pyrethrum Fields

2016 ◽  
Vol 106 (12) ◽  
pp. 1521-1529 ◽  
Author(s):  
Tamieka L. Pearce ◽  
Jason B. Scott ◽  
Frank S. Hay ◽  
Sarah J. Pethybridge
Keyword(s):  
Spatial Distribution ◽  
Mating Type ◽  
Tan Spot ◽  
Mating Types ◽  
Tanacetum Cinerariifolium ◽  
Polymerase Chain ◽  
Type Gene ◽  
Mat Genes

Tan spot of pyrethrum (Tanacetum cinerariifolium) is caused by the ascomycete Didymella tanaceti. To assess the evolutionary role of ascospores in the assumed asexual species, the structure and arrangement of mating-type (MAT) genes were examined. A single MAT1-1 or MAT1-2 idiomorph was identified in all isolates examined, indicating that the species is heterothallic. The idiomorphs were flanked upstream and downstream by regions encoding pyridoxamine phosphate oxidase-like and DNA lyase-like proteins, respectively. A multiplex MAT-specific polymerase chain reaction assay was developed and used to genotype 325 isolates collected within two transects in each of four fields in Tasmania, Australia. The ratio of isolates of each mating-type in each transect was consistent with a 1:1 ratio. The spatial distribution of the isolates of the two mating-types within each transect was random for all except one transect for MAT1-1 isolates, indicating that clonal patterns of each mating-type were absent. However, evidence of a reduced selection pressure on MAT1-1 isolates was observed, with a second haplotype of the MAT1-1-1 gene identified in 4.4% of MAT1-1 isolates. In vitro crosses between isolates with opposite mating-types failed to produce ascospores. Although the sexual morph could not be induced, the occurrence of both mating-types in equal frequencies suggested that a cryptic sexual mode of reproduction may occur within field populations.

scholarly journals Epigenetic Inheritance of Transcriptional Silencing and Switching Competence in Fission Yeast

Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 685-696 ◽  
Author(s):  
Geneviève Thon ◽  
Tove Friis
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Cumulative Effect ◽  
Transcriptional Silencing ◽  
Epigenetic Inheritance ◽  
Yeast Cells ◽  
Type Region ◽  
Epigenetic Events ◽  
Epigenetic Phenomenon ◽  
Gene Conversions

Epigenetic events allow the inheritance of phenotypic changes that are not caused by an alteration in DNA sequence. Here we characterize an epigenetic phenomenon occuring in the mating-type region of fission yeast. Cells of fission yeast switch between the P and M mating-type by interconverting their expressed mating-type cassette between two allelic forms, mat1-P and mat1-M. The switch results from gene conversions of mat1 by two silent cassettes, mat2-P and mat3-M, which are linked to each other and to mat1. Grewal and Klar observed that the ability to both switch mat1 and repress transcription near mat2-P and mat3-M was maintained epigenetically in a strain with an 8-kb deletion between mat2 and mat3. Using a strain very similar to theirs, we determined that interconversions between the switching- and silencing-proficient state and the switching and silencing-deficient state occurred less frequently than once per 1000 cell divisions. Although transcriptional silencing was alleviated by the 8-kb deletion, it was not abolished. We performed a mutant search and obtained a class of trans-acting mutations that displayed a strong cumulative effect with the 8-kb deletion. These mutations allow to assess the extent to which silencing is affected by the deletion and provide new insights on the redundancy of the silencing mechanism.

Mating-type gene switching in a homothallic fission yeast

1984 ◽  
Vol 110 (2) ◽  
pp. 299-312 ◽  
Author(s):  
Byron F. Johnson ◽  
G.B. Calleja ◽  
M. Zuker
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Mating Type Gene ◽  
Type Gene ◽  
Gene Switching

scholarly journals Actin-depolymerizing Protein Adf1 Is Required for Formation and Maintenance of the Contractile Ring during Cytokinesis in Fission Yeast

2006 ◽  
Vol 17 (4) ◽  
pp. 1933-1945 ◽  
Author(s):  
Kentaro Nakano ◽  
Issei Mabuchi
Keyword(s):  
Actin Cytoskeleton ◽  
Fission Yeast ◽  
Actin Filaments ◽  
Myosin Ii ◽  
Yeast Cells ◽  
Contractile Ring ◽  
Capping Protein ◽  
Division Site ◽  
Family Protein

The role of the actin-depolymerizing factor (ADF)/cofilin-family protein Adf1 in cytokinesis of fission yeast cells was studied. Adf1 was required for accumulation of actin at the division site by depolymerizing actin at the cell ends, assembly of the contractile ring through severing actin filaments, and maintenance of the contractile ring once formed. Genetic and cytological analyses suggested that it collaborates with profilin and capping protein in the mitotic reorganization of the actin cytoskeleton. Furthermore, it was unexpectedly found that Adf1 and myosin-II also collaborate in assembling the contractile ring. Tropomyosin was shown to antagonize the function of Adf1 in the contractile ring. We propose that formation and maintenance of the contractile ring are achieved by a balanced collaboration of these proteins.

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