Characterization of the Wtm proteins, a novel family of Saccharomyces cerevisiae transcriptional modulators with roles in meiotic regulation and silencing.
Transcription is regulated by the complex interplay of repressors and activators. Much of this regulation is carried out by, in addition to gene-specific factors, complexes of more general transcriptional modulators. Here we present the characterization of a novel family of transcriptional regulators in yeast. Wtm1p (WD repeat-containing transcriptional modulator) was identified as a protein present in a large nuclear complex. This protein has two homologs, Wtm2p and Wtm3p, which probably arose by gene duplications. Deletion of these genes affects transcriptional repression at several loci, including derepression of IME2, a meiotic gene normally repressed in haploid cells. Targeting of these proteins to DNA resulted in a dramatic repression of activated transcription. In common with a mutation in the histone deacetylase RPD3, wtm mutants showed increased repression at the silent mating-type locus, HMR, and at telomeres. Although all three Wtm proteins could act as transcriptional repressors, Wtm3p, which is the least homologous, appeared to have functions separate from those of the other two. Wtm3p did not appear to be complexed with the other two proteins, was essential for IME2 repression, and could not efficiently repress transcription in the absence of the other Wtm proteins. These data suggested that Wtm1p and Wtm2p are repressors and that Wtm3p has different effects on transcription at different loci.
Pemberton
L F
LF
Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021, USA. pemberl@rockvax.rockefeller.edu
Blobel
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G
D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000737:chemistry; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D005800:Genes, Fungal / Q000235:genetics; D049770:Genes, Mating Type, Fungal; D006655:Histone Deacetylases; D047908:Intracellular Signaling Peptides and Proteins; D008540:Meiosis / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D009154:Mutation; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D016615:Telomere; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C462439:UME1 protein, S cerevisiae; C107277:Wtm1 protein, S cerevisiae; C107278:Wtm2 protein, S cerevisiae; D011494:Protein Kinases; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C071665:RPD3 protein, S cerevisiae; D006655:Histone Deacetylases