Histone H3 lysine 4 methylation is mediated by Set1 and required for cell growth and rDNA silencing in Saccharomyces cerevisiae

  1. Scott D. Briggs1,
  2. Mary Bryk2,
  3. Brian D. Strahl1,
  4. Wang L. Cheung1,
  5. Judith K. Davie3,
  6. Sharon Y.R. Dent3,
  7. Fred Winston2, and
  8. C. David Allis1,4
  1. 1Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, Virginia 22908, USA; 2Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; 3Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA

Abstract

Histone methylation is known to be associated with both transcriptionally active and repressive chromatin states. Recent studies have identified SET domain–containing proteins such as SUV39H1 and Clr4 as mediators of H3 lysine 9 (Lys9) methylation and heterochromatin formation. Interestingly, H3 Lys9 methylation is not observed from bulk histones isolated from asynchronous populations ofSaccharomyces cerevisiae or Tetrahymena thermophila. In contrast, H3 lysine 4 (Lys4) methylation is a predominant modification in these smaller eukaryotes. To identify the responsible methyltransferase(s) and to gain insight into the function of H3 Lys4 methylation, we have developed a histone H3 Lys4 methyl-specific antiserum. With this antiserum, we show that deletion of SET1, but not of other putative SET domain–containing genes, in S. cerevisiae, results in the complete abolishment of H3 Lys4 methylation in vivo. Furthermore, loss of H3 Lys4 methylation in aset1Δ strain can be rescued by SET1. Analysis of histone H3 mutations at Lys4 revealed a slow-growth defect similar to aset1Δ strain. Chromatin immunoprecipitation assays show that H3 Lys4 methylation is present at the rDNA locus and that Set1-mediated H3 Lys4 methylation is required for repression of RNA polymerase II transcription within rDNA. Taken together, these data suggest that Set1-mediated H3 Lys4 methylation is required for normal cell growth and transcriptional silencing.

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Footnotes

  • 4 Corresponding author.

  • E-MAIL allis{at}virginia.edu; FAX (804) 924-5069.

  • Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.940201.

    • Received August 23, 2001.
    • Accepted November 5, 2001.
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