Multiple independent regulatory pathways control UBI4 expression after heat shock in Saccharomyces cerevisiae.
Transcription of the polyubiquitin gene UBI4 of Saccharomyces cerevisiae is strongly induced by a variety of environmental stresses, such as heat shock, nutrient depletion and exposure to DNA-damaging agents. This transcriptional response of UBI4 is likely to be the primary mechanism for increasing the pool of ubiquitin for degradation of stress-damaged proteins. Deletion and promoter fusion studies of the 5' regulatory sequences indicated that two different elements, heat shock elements (HSEs) and stress response element (STREs), contributed independently to heat shock regulation of the UBI4 gene. In the absence of HSEs, STRE sequences localized to the intervals -264 to -238 and -215 to -183 were needed for stress control of transcription after heat shock. Site-directed mutagenesis of the STRE (AG4) at -252 to -248 abolished heat shock induction of UBI4 transcription. Northern analysis demonstrated that cells containing either a temperature-sensitive HSF or non-functional Msn2p/Msn4p transcription factors induced high levels of UBI4 transcripts after heat shock. In cells deficient in both heat stress pathways, heat-induced UBI4 transcript levels were considerably lower but not abolished, suggesting a role for another factor(s) in stress control of its expression.
Department of Biological Chemistry, School of Medicine, University of California, Los Angeles 90095, USA.
J R
JR
Simon
J M
JM
Treger
K
K
McEntee
D000199:Actins / Q000235:genetics; D029681:Arabidopsis Proteins; D001704:Biopolymers / Q000235:genetics* / Q000502:physiology*; D015152:Blotting, Northern; D004268:DNA-Binding Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed; D025821:Polyubiquitin; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics; D014452:Ubiquitins / Q000235:genetics* / Q000502:physiology*; D001616:beta-Galactosidase / Q000032:analysis
C098619:AAC1 protein, Arabidopsis; D000199:Actins; D029681:Arabidopsis Proteins; D001704:Biopolymers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; C081935:MSN2 protein, S cerevisiae; C081335:STD1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014452:Ubiquitins; D025821:Polyubiquitin; D001616:beta-Galactosidase