Faculty Opinions recommendation of Fission yeast Scm3 mediates stable assembly of Cnp1/CENP-A into centromeric chromatin.

Centromeric chromatin in fission yeast is distinguished by the presence of nucleosomes containing the histone H3 variant Cnp1CENP-A. Cell cycle–specific deposition of Cnp1 requires the Mis16–Mis18–Mis19 complex, which is thought to direct recruitment of Scm3-chaperoned Cnp1/histone H4 dimers to DNA. Here, we present the structure of the essential Mis18 partner protein Mis19 and describe its interaction with Mis16, revealing a bipartite-binding site. We provide data on the stoichiometry and overall architecture of the complex and provide detailed insights into the Mis18–Mis19 interface.

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Defects in Components of the Proteasome Enhance Transcriptional Silencing at Fission Yeast Centromeres and Impair Chromosome Segregation

Molecular and Cellular Biology ◽

10.1128/mcb.19.7.5155 ◽

1999 ◽

Vol 19 (7) ◽

pp. 5155-5165 ◽

Cited By ~ 12

Author(s):

Jean-Paul Javerzat ◽

Gordon McGurk ◽

Gwen Cranston ◽

Christian Barreau ◽

Pascal Bernard ◽

...

Keyword(s):

Fission Yeast ◽

Sister Chromatid ◽

Position Effect ◽

Transcriptional Silencing ◽

Position Effect Variegation ◽

Centromeric Chromatin ◽

Centromere Function ◽

Chromatid Cohesion ◽

Sister Chromatid Separation ◽

Elevated Rate

ABSTRACT Fission yeast centromeres are transcriptionally silent and form a heterochromatin-like structure essential for normal centromere function; this appears analogous to heterochromatin and position effect variegation in other eukaryotes. Conditional mutations in three genes designated cep (centromere enhancer of position effect) were found to enhance transcriptional silencing within centromeres. Cloning of the cep1 + andcep2 + genes by functional complementation revealed that they are identical to the previously described genespad1 + and mts2 +, respectively, which both encode subunits of the proteasome 19S cap. Like Mts2 and Mts4, epitope-tagged Cep1/Pad1 localizes to or near the nuclear envelope throughout the cell cycle. The cep mutants display a range of phenotypes depending on the temperature. Silencing within the central domain of centromeres is increased at 36°C. This suggests that the proteasome is involved in regulating silencing and thus centromeric chromatin architecture, possibly by lowering the level of some chromatin-associated protein by ubiquitin-dependent degradation. This is the first report of defective proteasome function affecting heterochromatin-mediated transcriptional silencing. At 36 and 32°C, the cep mutants lose chromosomes at an elevated rate, and at 18°C, the mutants are cryosensitive for growth. Cytological analysis at 18°C revealed a defect in sister chromatid separation while other mitotic events occurred normally, indicating that cep mutations might interfere specifically with the degradation of inhibitor(s) of sister chromatid separation. These observations suggest that 19S subunits confer a level of substrate specificity on the proteasome and raise the possibility of a link between components involved in centromere architecture and sister chromatid cohesion.

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Centromeric chromatin in fission yeast

Frontiers in Bioscience ◽

10.2741/2977 ◽

2008 ◽

Vol Volume (13) ◽

pp. 3896

Author(s):

., . .

Keyword(s):

Fission Yeast ◽

Centromeric Chromatin

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Fission Yeast Scm3 Mediates Stable Assembly of Cnp1/CENP-A into Centromeric Chromatin

Molecular Cell ◽

10.1016/j.molcel.2009.01.017 ◽

2009 ◽

Vol 33 (3) ◽

pp. 287-298 ◽

Cited By ~ 136

Author(s):

Jessica S. Williams ◽

Takeshi Hayashi ◽

Mitsuhiro Yanagida ◽

Paul Russell

Keyword(s):

Fission Yeast ◽

Centromeric Chromatin

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Intricate regulation on epigenetic stability of the subtelomeric heterochromatin and the centromeric chromatin in fission yeast

Current Genetics ◽

10.1007/s00294-018-0886-9 ◽

2018 ◽

Vol 65 (2) ◽

pp. 381-386

Author(s):

Min Lu ◽

Xiangwei He

Keyword(s):

Fission Yeast ◽

Centromeric Chromatin ◽

Subtelomeric Heterochromatin

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The fission yeast nucleoporin Alm1 is required for proteasomal degradation of kinetochore components

The Journal of Cell Biology ◽

10.1083/jcb.201612194 ◽

2017 ◽

Vol 216 (11) ◽

pp. 3591-3608 ◽

Cited By ~ 6

Author(s):

Silvia Salas-Pino ◽

Paola Gallardo ◽

Ramón R. Barrales ◽

Sigurd Braun ◽

Rafael R. Daga

Keyword(s):

Nuclear Envelope ◽

Fission Yeast ◽

Chromosome Segregation ◽

Mitotic Spindle ◽

Essential Role ◽

Spindle Assembly Checkpoint ◽

Proteasomal Degradation ◽

Nuclear Pore ◽

Checkpoint Activation ◽

Centromeric Chromatin

Kinetochores (KTs) are large multiprotein complexes that constitute the interface between centromeric chromatin and the mitotic spindle during chromosome segregation. In spite of their essential role, little is known about how centromeres and KTs are assembled and how their precise stoichiometry is regulated. In this study, we show that the nuclear pore basket component Alm1 is required to maintain both the proteasome and its anchor, Cut8, at the nuclear envelope, which in turn regulates proteostasis of certain inner KT components. Consistently, alm1-deleted cells show increased levels of KT proteins, including CENP-CCnp3, spindle assembly checkpoint activation, and chromosome segregation defects. Our data demonstrate a novel function of the nucleoporin Alm1 in proteasome localization required for KT homeostasis.

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