
<ArticleTitle><prot>Upc2p</prot> and <prot>Ecm22p</prot>, dual regulators of sterol biosynthesis in Saccharomyces cerevisiae.</ArticleTitle>
<AbstractText>Sterol levels affect the expression of many genes in yeast and humans. We found that the paralogous transcription factors <prot>Upc2p</prot> and <prot>Ecm22p</prot> of yeast were <prot>sterol regulatory element (SRE) binding proteins</prot> (<prot>SREBPs</prot>) responsible for regulating transcription of the sterol biosynthetic genes <prot>ERG2</prot> and <prot>ERG3</prot>. We defined a 7-bp SRE common to these and other genes, including many genes involved in sterol biosynthesis. <prot>Upc2p</prot> and <prot>Ecm22p</prot> activated <prot>ERG2</prot> expression by binding directly to this element in the <prot>ERG2</prot> promoter. <prot>Upc2p</prot> and <prot>Ecm22p</prot> may thereby coordinately regulate genes involved in sterol homeostasis in yeast. <prot>Ecm22p</prot> and <prot>Upc2p</prot> are members of the fungus-specific Zn[2]-Cys[6] binuclear cluster family of transcription factors and share no homology to the analogous proteins, <prot>SREBPs</prot>, that are responsible for transcriptional regulation by sterols in humans. These results suggest that Saccharomyces cerevisiae and human cells regulate sterol synthesis by different mechanisms.</AbstractText>
