title: Transcription regulation of the Saccharomyces cerevisiae PHO5 gene by the Ino2p and Ino4p basic helix-loop-helix proteins.
abstract: The Saccharomyces cerevisiae PHO5 gene product accounts for a majority of the acid phosphatase activity. Its expression is induced by the basic helix-loop-helix (bHLH) protein, Pho4p, in response to phosphate depletion. Pho4p binds predominantly to two UAS elements (UASp1 at -356 and UASp2 at -247) in the PHO5 promoter. Previous studies from our lab have shown cross-regulation of different biological processes by bHLH proteins. This study tested the ability of all yeast bHLH proteins to regulate PHO5 expression and identified inositol-mediated regulation via the Ino2p/Ino4p bHLH proteins. Ino2p/Ino4p are known regulators of phospholipid biosynthetic genes. Genetic epistasis experiments showed that regulation by inositol required a third UAS site (UASp3 at -194). ChIP assays showed that Ino2p:Ino4p bind the PHO5 promoter and that this binding is dependent on Pho4p binding. These results demonstrate that phospholipid biosynthesis is co-ordinated with phosphate utilization via the bHLH proteins.
authors.affiliation: Department of Microbiology, and Molecular Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.forename: Aishwarya
authors.initials: A
authors.lastname: Swaminathan
authors.forename: John M
authors.initials: JM
authors.lastname: Lopes
mesh_terms: D000135:Acid Phosphatase / Q000096:biosynthesis*; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D004271:DNA, Fungal / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D015966:Gene Expression Regulation, Fungal; D007294:Inositol / Q000378:metabolism*; D008954:Models, Biological; D010743:Phospholipids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D000135:Acid Phosphatase; D051792:Basic Helix-Loop-Helix Proteins; D004271:DNA, Fungal; D007294:Inositol; D010743:Phospholipids; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C095723:INO2 protein, S cerevisiae; C063311:INO4 protein, S cerevisiae; C488916:PHO5 protein, S cerevisiae