Met31p and Met32p, two related zinc finger proteins, are involved in transcriptional regulation of yeast sulfur amino acid metabolism.
Sulfur amino acid metabolism in Saccharomyces cerevisiae is regulated by the level of intracellular S-adenosylmethionine (AdoMet). Two cis-acting elements have been previously identified within the 5' upstream regions of the structural genes of the sulfur network. The first contains the CACGTG motif and is the target of the transcription activation complex Cbflp-Met4p-Met28p. We report here the identification of two new factors, Met31p and Met32p, that recognize the second cis-acting element. Met31p was isolated through the use of the one-hybrid method, while Met32p was identified during the analysis of the yeast methionine transport system. Met31p and Met32p are highly related zinc finger-containing proteins. Both LexA-Met31p and LexA-Met32p fusion proteins activate the transcription of a LexAop-containing promoter in a Met4p-dependent manner. Northern blot analyses of cells that do not express either Met31p and/or Met32p suggest that the function of the two proteins during the transcriptional regulation of the sulfur network varies from one gene to the other. While the expression of both the MET3 and MET14 genes was shown to strictly depend upon the presence of either Met31p or Met32p, the transcription of the MET25 gene is constitutive in cells lacking both Met31p and Met32p. These results therefore emphasise the diversity of the mechanisms allowing regulation of the expression of the methionine biosynthetic genes.
Blaiseau
P L
PL
Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
Isnard
A D
AD
Surdin-Kerjan
Y
Y
Thomas
D
D
D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D008715:Methionine / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D012436:S-Adenosylmethionine / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C106764:Met31 protein, S cerevisiae; C106765:Met32 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012436:S-Adenosylmethionine; D008715:Methionine