Glucose Repression of STA1 Expression Is Mediated by the Nrg1 and Sfl1 Repressors and the Srb8-11 Complex
AUTOR(ES)
Kim, Tae Soo
FONTE
American Society for Microbiology
RESUMO
In the yeast Saccharomyces diastaticus, expression of the STA1 gene, which encodes an extracellular glucoamylase, is negatively regulated by glucose. Here we demonstrate that glucose-dependent repression of STA1 expression is imposed by both Sfl1 and Nrg1, which serve as direct transcriptional repressors. We show that Nrg1 acts only on UAS1, and Sfl1 acts only on UAS2, in the STA1 promoter. When bound to its specific site, Sfl1 (but not Nrg1) prevents the binding to UAS2 of two transcriptional activators, Ste12 and Tec1, required for STA1 expression. We also found that Sfl1 contributes to STA1 repression by binding to the promoter and inhibiting the expression of FLO8, a gene that encodes a third transcriptional activator involved in STA1 expression. In addition, we show that the levels of Nrg1 and Sfl1 increase in glucose-grown cells, suggesting that the effects of glucose are mediated, at least in part, through an increase in the abundance of these repressors. NRG1 and SFL1 expression requires the Srb8-11 complex, and correspondingly, the Srb8-11 complex is also necessary for STA1 repression. However, our evidence indicates that the Srb8-11 complex does not associate with either the SFL1 or the NRG1 promoter and thus plays an indirect role in activating NRG1 and SFL1 expression.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=507009Documentos Relacionados
- Nrg1 Is a Transcriptional Repressor for Glucose Repression of STA1 Gene Expression in Saccharomyces cerevisiae
- Recruitment of the Swi/Snf Complex by Ste12-Tec1 Promotes Flo8-Mss11-Mediated Activation of STA1 Expression
- NRG1 is required for glucose repression of the SUC2 and GAL genes of Saccharomyces cerevisiae
- Snf1 Protein Kinase and the Repressors Nrg1 and Nrg2 Regulate FLO11, Haploid Invasive Growth, and Diploid Pseudohyphal Differentiation
- Nrg1 and Nrg2 Transcriptional Repressors Are Differently Regulated in Response to Carbon Source