Abstract
Heterochromatin performs a central role in chromosome segregation and stability by promoting cohesion at centromeres. Establishment of both heterochromatin-mediated silencing and cohesion requires passage through S phase, although the mechanism is unknown. Here we demonstrate that Schizosaccharomyces pombe Hsk1 (CDC7), a conserved Dbf4-dependent protein kinase (DDK) that regulates replication initiation, interacts with and phosphorylates the heterochromatin protein 1 (HP1) equivalent Swi6 (ref. 6). Hsk1 and its regulatory subunit Dfp1 function downstream of Swi6 localization to promote heterochromatin function and cohesion specifically at centromeres. This role for Hsk1-Dfp1 is separable from its replication initiation activity, providing a temporal link between S phase and centromere cohesion that is mediated by heterochromatin.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Division / genetics*
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Centromere / genetics*
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism
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Chromosome Segregation / genetics*
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DNA Replication / genetics
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Heterochromatin / genetics*
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein Subunits / genetics
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Protein Subunits / metabolism
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S Phase / genetics
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism*
Substances
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Cell Cycle Proteins
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Chromosomal Proteins, Non-Histone
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Heterochromatin
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Protein Subunits
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Schizosaccharomyces pombe Proteins
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Swi6 protein, S pombe
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HSK1 protein, S pombe
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Protein Serine-Threonine Kinases