Abstract
The Smc5/6 holocomplex executes key functions in genome maintenance that include ensuring the faithful segregation of chromosomes at mitosis and facilitating critical DNA repair pathways. Smc5/6 is essential for viability and therefore, dissecting its chromosome segregation and DNA repair roles has been challenging. We have identified distinct epigenetic and post-translational modifications that delineate roles for fission yeast Smc5/6 in centromere function, versus replication fork-associated DNA repair. We monitored Smc5/6 subnuclear and genomic localization in response to different replicative stresses, using fluorescence microscopy and chromatin immunoprecipitation (ChIP)-on-chip methods. Following hydroxyurea treatment, and during an unperturbed S phase, Smc5/6 is transiently enriched at the heterochromatic outer repeats of centromeres in an H3-K9 methylation-dependent manner. In contrast, methyl methanesulphonate treatment induces the accumulation of Smc5/6 at subtelomeres, in an Nse2 SUMO ligase-dependent, but H3-K9 methylation-independent manner. Finally, we determine that Smc5/6 loads at all genomic tDNAs, a phenomenon that requires intact consensus TFIIIC-binding sites in the tDNAs.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Nucleus / metabolism
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Cell Nucleus / ultrastructure
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Centromere / metabolism*
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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DNA Replication
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DNA, Fungal / chemistry
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DNA, Fungal / metabolism
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Heterochromatin / metabolism*
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Hydroxyurea / metabolism
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Methyl Methanesulfonate / metabolism
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Mutagens / metabolism
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Nucleic Acid Synthesis Inhibitors / metabolism
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Schizosaccharomyces / cytology
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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*
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Small Ubiquitin-Related Modifier Proteins / genetics
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Small Ubiquitin-Related Modifier Proteins / metabolism*
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Telomere / metabolism*
Substances
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Carrier Proteins
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Cell Cycle Proteins
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Chromosomal Proteins, Non-Histone
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DNA, Fungal
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Heterochromatin
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Mutagens
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Nse2 protein, S pombe
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Nse4 protein, S pombe
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Nucleic Acid Synthesis Inhibitors
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Schizosaccharomyces pombe Proteins
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Small Ubiquitin-Related Modifier Proteins
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Smc5 protein, S pombe
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smc6 protein, S pombe
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Methyl Methanesulfonate
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Hydroxyurea