Abstract
The PCH2 gene of Saccharomyces cerevisiae is required for the meiotic checkpoint that prevents chromosome segregation when recombination and chromosome synapsis are defective. Mutation of PCH2 relieves the checkpoint-induced pachytene arrest of the zip1, zip2, and dmc1 mutants, resulting in chromosome missegregation and low spore viability. Most of the Pch2 protein localizes to the nucleolus, where it represses meiotic interhomolog recombination in the ribosomal DNA, apparently by excluding the meiosis-specific Hop1 protein. Nucleolar localization of Pch2 depends on the silencing factor Sir2, and mutation of SIR2 also bypasses the zip1 pachytene arrest. Under certain circumstances, Sir3-dependent localization of Pch2 to telomeres also provides checkpoint function. These unexpected findings link the nucleolus, chromatin silencing, and the pachytene checkpoint.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Cell Cycle Proteins*
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Cell Nucleolus / chemistry
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Cell Nucleolus / genetics
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Chromatin / chemistry
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Chromatin / genetics*
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DNA, Ribosomal / analysis
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DNA-Binding Proteins / analysis
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DNA-Binding Proteins / genetics
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Fungal Proteins / analysis
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Fungal Proteins / genetics
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Gene Expression Regulation, Fungal
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Genes, Fungal / physiology*
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Histone Deacetylases*
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Meiosis / genetics*
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Mutagenesis / physiology
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Nuclear Proteins
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Recombination, Genetic / genetics
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae Proteins*
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Silent Information Regulator Proteins, Saccharomyces cerevisiae*
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Sirtuin 2
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Sirtuins
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Synaptonemal Complex / genetics
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Telomere / chemistry
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Telomere / genetics
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Trans-Activators / genetics
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Transcriptional Activation / physiology
Substances
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Cell Cycle Proteins
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Chromatin
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DMC1 protein, S cerevisiae
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DNA, Ribosomal
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DNA-Binding Proteins
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Fungal Proteins
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HOP1 protein, S cerevisiae
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Nuclear Proteins
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SIR3 protein, S cerevisiae
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SIR4 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Silent Information Regulator Proteins, Saccharomyces cerevisiae
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Trans-Activators
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Zip1 protein, S cerevisiae
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SIR2 protein, S cerevisiae
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Sirtuin 2
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Sirtuins
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Histone Deacetylases