The transcriptional coactivators SAGA, SWI/SNF, and mediator make distinct contributions to activation of glucose-repressed genes.
The paradigm of activation via ordered recruitment has evolved into a complicated picture as the influence of coactivators and chromatin structures on gene regulation becomes understood. We present here a comprehensive study of many elements of activation of ADH2 and FBP1, two glucose-regulated genes. We identify SWI/SNF as the major chromatin-remodeling complex at these genes, whereas SAGA (Spt-Ada-Gcn5-acetyltransferase complex) is required for stable recruitment of other coactivators. Mediator plays a crucial role in expression of both genes but does not affect chromatin remodeling. We found that Adr1 bound unaided by coactivators to ADH2, but Cat8 binding depended on coactivators at FBP1. Taken together, our results suggest that commonly regulated genes share many aspects of activation, but that gene-specific regulators or elements of promoter architecture may account for small differences in the mechanism of activation. Finally, we found that activator overexpression can compensate for the loss of SWI/SNF but not for the loss of SAGA.
Biddick
Rhiannon K
RK
Department of Biochemistry, University of Washington, Seattle, Washington 98105, USA.
Law
G Lynn
GL
Chin
Kevin Khaw Beng
KK
Young
Elton T
ET
D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D006597:Fructose-Bisphosphatase; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D005947:Glucose / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
C092600:CAT8 protein, S cerevisiae; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C507785:SAGA complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; C509911:ADH2 protein, S cerevisiae; D000426:Alcohol Dehydrogenase; C111172:FBP1 protein, S cerevisiae; D006597:Fructose-Bisphosphatase; D005947:Glucose