Orientation of “plus” genes at the mating-type locus in homothallic fission yeast

1978 ◽  
Vol 161 (3) ◽  
pp. 305-309 ◽  
Author(s):  
Richard Egel
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Type Locus ◽  
Mating Type Locus

scholarly journals The fission yeast heterochromatin protein Rik1 is required for telomere clustering during meiosis

2004 ◽  
Vol 165 (6) ◽  
pp. 759-765 ◽  
Author(s):  
Creighton T. Tuzon ◽  
Britta Borgstrom ◽  
Dietmar Weilguny ◽  
Richard Egel ◽  
Julia Promisel Cooper ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Sexual Differentiation ◽  
Histone H3 ◽  
Heterochromatin Protein ◽  
Type Locus ◽  
Heterochromatin Formation ◽  
Mating Type Locus ◽  
Telomere Protein ◽  
Chromosome Movements

Telomeres share the ability to silence nearby transcription with heterochromatin, but the requirement of heterochromatin proteins for most telomere functions is unknown. The fission yeast Rik1 protein is required for heterochromatin formation at centromeres and the mating-type locus, as it recruits the Clr4 histone methyltransferase, whose modification of histone H3 triggers binding by Swi6, a conserved protein involved in spreading of heterochromatin. Here, we demonstrate that Rik1 and Clr4, but not Swi6, are required along with the telomere protein Taz1 for crucial chromosome movements during meiosis. However, Rik1 is dispensable for the protective roles of telomeres in preventing chromosome end-fusion. Thus, a Swi6-independent heterochromatin function distinct from that at centromeres and the mating-type locus operates at telomeres during sexual differentiation.

scholarly journals The Mating-Type Proteins of Fission Yeast Induce Meiosis by Directly Activating mei3 Transcription

1998 ◽  
Vol 18 (12) ◽  
pp. 7317-7326 ◽  
Author(s):  
Willem J. van Heeckeren ◽  
David R. Dorris ◽  
Kevin Struhl
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Regulatory Element ◽  
Single Gene ◽  
Homeodomain Protein ◽  
Type Locus ◽  
Mating Type Locus ◽  
Positive Elements ◽  
Tata Sequence ◽  
Multiple Sequences

ABSTRACT Cell type control of meiotic gene regulation in the budding yeastSaccharomyces cerevisiae is mediated by a cascade of transcriptional repressors, a1-α2 and Rme1. Here, we investigate the analogous regulatory pathway in the fission yeastSchizosaccharomyces pombe by analyzing the promoter ofmei3, the single gene whose expression is sufficient to trigger meiosis. The mei3 promoter does not appear to contain a negative regulatory element that represses transcription in haploid cells. Instead, correct regulation of mei3transcription depends on a complex promoter that contains at least five positive elements upstream of the TATA sequence. These elements synergistically activate mei3 transcription, thereby constituting an on-off switch for the meiosis pathway. Element C is a large region containing multiple sequences that resemble binding sites for Mc, an HMG domain protein encoded by the mating-type locus. The function of element C is extremely sensitive to spacing changes but not to linker-scanning mutations, suggesting the possibility that Mc functions as an architectural transcription factor. Altered-specificity experiments indicate that element D interacts with Pm, a homeodomain protein encoded by the mating-type locus. This indicates that Pm functions as a direct activator of the meiosis pathway, whereas the homologous mating-type protein in S. cerevisiae (α2) functions as a repressor. Thus, despite the strong similarities between the mating-type loci of S. cerevisiae and S. pombe, the regulatory logic that governs the tight control of the key meiosis-inducing genes in these organisms is completely different.

scholarly journals RNA Interference (RNAi)-Dependent and RNAi-Independent Association of the Chp1 Chromodomain Protein with Distinct Heterochromatic Loci in Fission Yeast

2005 ◽  
Vol 25 (6) ◽  
pp. 2331-2346 ◽  
Author(s):  
Victoria J. Petrie ◽  
Jeffrey D. Wuitschick ◽  
Cheryl D. Givens ◽  
Aaron M. Kosinski ◽  
Janet F. Partridge
Keyword(s):  
Rna Interference ◽  
Fission Yeast ◽  
Mating Type ◽  
Histone H3 ◽  
Protein Component ◽  
Centromeric Heterochromatin ◽  
Rnai Pathway ◽  
Type Locus ◽  
Mating Type Locus ◽  
Terminal Domain

ABSTRACT The establishment of centromeric heterochromatin in the fission yeast Schizosaccharomyces pombe is dependent on the RNA interference (RNAi) pathway. Dicer cleaves centromeric transcripts to produce short interfering RNAs (siRNAs) that actively recruit components of heterochromatin to centromeres. Both centromeric siRNAs and the heterochromatin component Chp1 are components of the RITS (RNA-induced initiation of transcriptional gene silencing) complex, and the association of RITS with centromeres is linked to Dicer activity. In turn, centromeric binding of RITS promotes Clr4-mediated methylation of histone H3 lysine 9 (K9), recruitment of Swi6, and formation of heterochromatin. Similar to centromeres, the mating type locus (Mat) is coated in K9-methylated histone H3 and is bound by Swi6. Here we report that Chp1 associates with the mating type locus and telomeres and that Chp1 localization to heterochromatin depends on its chromodomain and the C-terminal domain of the protein. Another protein component of the RITS complex, Tas3, also binds to Mat and telomeres. Tas3 interacts with Chp1 through the C-terminal domain of Chp1, and this interaction is necessary for Tas3 stability. Interestingly, in cells lacking the Argonaute (Ago1) protein component of the RITS complex, or lacking Dicer (and hence siRNAs), Chp1 and Tas3 can still bind to noncentromeric loci, although their association with centromeres is lost. Thus, Chp1 and Tas3 exist as an Ago1-independent subcomplex that associates with noncentromeric heterochromatin independently of the RNAi pathway.

scholarly journals TOR complex 2 in fission yeast is required for chromatin-mediated gene silencing and assembly of heterochromatic domains at subtelomeres

2018 ◽  
Vol 293 (21) ◽  
pp. 8138-8150 ◽  
Author(s):  
Adiel Cohen ◽  
Aline Habib ◽  
Dana Laor ◽  
Sudhanshu Yadav ◽  
Martin Kupiec ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Gene Silencing ◽  
Fission Yeast ◽  
Mating Type ◽  
Transcriptional Level ◽  
Type Locus ◽  
Pol Ii ◽  
Mating Type Locus ◽  
Histone 3 ◽  
Subtelomeric Regions

The conserved serine/threonine protein kinase target of rapamycin (TOR) is a major regulator of eukaryotic cellular and organismal growth and a valuable target for drug therapy. TOR forms the core of two evolutionary conserved complexes, TOR complex 1 (TORC1) and TORC2. In the fission yeast Schizosaccharomyces pombe, TORC2 responds to glucose levels and, by activating the protein kinase Gad8 (an orthologue of human AKT), is required for well-regulated cell cycle progression, starvation responses, and cell survival. Here, we report that TORC2–Gad8 is also required for gene silencing and the formation of heterochromatin at the S. pombe mating-type locus and at subtelomeric regions. Deletion of TORC2–Gad8 resulted in loss of the heterochromatic modification of histone 3 lysine 9 dimethylation (H3K9me2) and an increase in euchromatic modifications, including histone 3 lysine 4 trimethylation (H3K4me3) and histone 4 lysine 16 acetylation (H4K16Ac). Accumulation of RNA polymerase II (Pol II) at subtelomeric genes in TORC2–Gad8 mutant cells indicated a defect in silencing at the transcriptional level. Moreover, a concurrent decrease in histone 4 lysine 20 dimethylation (H4K20me2) suggested elevated histone turnover. Loss of gene silencing in cells lacking TORC2–Gad8 is partially suppressed by loss of the anti-silencer Epe1 and fully suppressed by loss of the Pol II–associated Paf1 complex, two chromatin regulators that have been implicated in heterochromatin stability and spreading. Taken together, our findings suggest that TORC2–Gad8 signaling contributes to epigenetic stability at subtelomeric regions and the mating-type locus in S. pombe.

scholarly journals Molecular signature of the imprintosome complex at the mating-type locus in fission yeast

2018 ◽  
Vol 5 (4) ◽  
pp. 169-183 ◽  
Author(s):  
Célia Raimondi ◽  
Bernd Jagla ◽  
Caroline Proux ◽  
Hervé Waxin ◽  
Serge Gangloff ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Mating Type ◽  
Molecular Signature ◽  
Type Locus ◽  
Mating Type Locus
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