The Ccr4-not complex independently controls both Msn2-dependent transcriptional activation - via a newly identified Glc7/Bud14 type I protein phosphatase module - and TFIID promoter distribution
Lenssen, E × James, N Pedruzzi, N Dubouloz, F Cameroni, E Bisig, R Maillet, L Werner, M Roosen, Johnny Petrovic, K Winderickx, Joris Collart, MA De Virgilio, C #
Amer soc microbiology
Molecular and cellular biology vol:25 issue:1 pages:488-498
The Ccr4-Not complex is a conserved global regulator of gene expression, which serves as a regulatory platform that senses and/or transmits nutrient and stress signals to various downstream effectors. Presumed effectors of this complex in yeast are TFIID, a general transcription factor that associates with the core promoter, and Msn2, a key transcription factor that regulates expression of stress-responsive element (STRE)-controlled genes. Here we show that the constitutively high level of STRE-driven expression in cer4-not mutants results from two independent effects. Accordingly, loss of Ccr4-Not function causes a dramatic Msn2-independent redistribution of TFIID on promoters with a particular bias for STRE-controlled over ribosomal protein gene promoters. In parallel, loss of Ccr4-Not complex function results in an alteration of the posttranslational modification status of Msn2, which depends on the type I protein phosphatase Glc7 and its newly identified subunit Bud14. Tests of epistasis as well as transcriptional analyses of Bud14-dependent transcription support a model in which the Ccr4-Not complex prevents activation of Msn2 via inhibition of the Budl4/Glc7 module in exponentially growing cells. Thus, increased activity of STRE genes in ccr4-not mutants may result from both altered general distribution of TFIID and unscheduled activation of NIsn2.