An unusual form of transcriptional silencing in yeast ribosomal DNA

Jeffrey S. Smith, Jef D. Boeke

    Research output: Contribution to journalArticle

    Abstract

    Generalized transcriptional repression of large chromosomal regions in Saccharomyces cerevisiae occurs at the silent mating loci and at telomeres and is mediated by the silent information regulator (SIR) genes. We have identified a novel form of transcriptional silencing in S. cerevisiae in the ribosomal DNA (rDNA) tandem array. Ty1 retrotransposons marked with a weakened URA3 gene (Ty1-mURA3) efficiently integrated into rDNA. The mURA3 marker in rDNA was transcriptionally silenced in a SIR2-dependent manner. MET15 and LEU2 were also partially silenced, indicating that rDNA silencing may be quite general. Deletion of SIR4 enhanced mURA3 and MET15 silencing, but deletion of SIR1 or SIR3 did not affect silencing, indicating that the mechanism of silencing differs from that at telomeres and silent mating loci. Deletion of SIR2 resulted in increased psoralen cross-linking of the rDNA in vivo, suggesting that a specific chromatin structure in rDNA down-regulates polymerase II promoters.

    Original languageEnglish (US)
    Pages (from-to)241-254
    Number of pages14
    JournalGenes and Development
    Volume11
    Issue number2
    DOIs
    StatePublished - Jan 15 1997

    Keywords

    • S. cerevisiae
    • SIR genes
    • Transcriptional repression
    • silent mating loci
    • yeast ribosomal DNA

    ASJC Scopus subject areas

    • Genetics
    • Developmental Biology

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