title: The yeast UME6 gene is required for both negative and positive transcriptional regulation of phospholipid biosynthetic gene expression.
abstract: In Saccharomyces cerevisiae, regulation of the phospholipid biosynthetic genes, INO1, CHO1, CHO2 and OPI3, is known to occur at the level of transcript abundance. Derepression in response to inositol deprivation requires the INO2 and INO4 regulatory genes. Repression in response to inositol supplementation requires the OPI1 regulatory gene. Here, we examined the role of the UME6 global negative regulatory gene in expression of the phospholipid biosynthetic genes. These studies were stimulated by the finding that the INO1 promoter included a UME6 cognate cis-acting regulatory sequence (URS1). We found that the UME6 negative regulatory gene was involved in regulation of phospholipid biosynthetic gene expression through two distinct regulatory pathways. One pathway was the direct repression of INO1 expression through the URS1 element. Surprisingly, the UME6 gene was also required for derepression of CHO1, CHO2 and OPI3 gene expression. Consistent with this observation, the UME6 gene was required for wild-type levels of expression of the INO2 positive regulatory gene. Therefore, the UME6 gene has both a negative and a positive role in regulating phospholipid biosynthesis.
authors.affiliation: Department of Molecular and Cellular Biochemistry, Loyola University of Chicago, Maywood, IL 60153, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Jackson
authors.forename: J M
authors.initials: JM
authors.lastname: Lopes
mesh_terms: D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D007294:Inositol / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010743:Phospholipids / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D007294:Inositol; D008869:Microtubule-Associated Proteins; D010743:Phospholipids; D012333:RNA, Messenger; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C095723:INO2 protein, S cerevisiae; C089979:UME6 protein, S cerevisiae