title: The yeast Hot1 transcription factor is critical for activating a single target gene, STL1.
abstract: Transcription factors are commonly activated by signal transduction cascades and induce expression of many genes. They therefore play critical roles in determining the cell's fate. The yeast Hog1 MAP kinase pathway is believed to control the transcription of hundreds of genes via several transcription factors. To identify the bona fide target genes of Hog1, we inducibly expressed the spontaneously active variant Hog1(D170A+F318L) in cells lacking the Hog1 activator Pbs2. This system allowed monitoring the effects of Hog1 by itself. Expression of Hog1(D170A+F318L) in pbs2∆ cells imposed induction of just 105 and suppression of only 26 transcripts by at least twofold. We looked for the Hog1-responsive element within the promoter of the most highly induced gene, STL1 (88-fold). A novel Hog1 responsive element (HoRE) was identified and shown to be the direct target of the transcription factor Hot1. Unexpectedly, we could not find this HoRE in any other yeast promoter. In addition, the only gene whose expression was abolished in hot1∆ cells was STL1. Thus Hot1 is essential for transcription of just one gene, STL1. Hot1 may represent a class of transcription factors that are essential for transcription of a very few genes or even just one.
authors.affiliation: CREATE-NUS-HUJ Cellular and Molecular Mechanisms of Inflammation Programme, National University of Singapore, Singapore 138602 Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456.
authors.forename: Chen
authors.initials: C
authors.lastname: Bai
authors.affiliation: Department of Biological Chemistry, Institute of Life Science, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Masha
authors.initials: M
authors.lastname: Tesker
authors.affiliation: CREATE-NUS-HUJ Cellular and Molecular Mechanisms of Inflammation Programme, National University of Singapore, Singapore 138602 Department of Biological Chemistry, Institute of Life Science, Hebrew University of Jerusalem, Jerusalem 91904, Israel engelber@mail.huji.ac.il.
authors.forename: David
authors.initials: D
authors.lastname: Engelberg
mesh_terms: D015966:Gene Expression Regulation, Fungal; D026901:Membrane Transport Proteins / Q000235:genetics*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: C120535:HOT1 protein, S cerevisiae; D026901:Membrane Transport Proteins; C470555:STL1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases