A regulatory shortcut between the Snf1 protein kinase and RNA polymerase II holoenzyme.
RNA polymerase II holoenzymes respond to activators and repressors that are regulated by signaling pathways. Here we present evidence for a "shortcut" mechanism in which the Snf1 protein kinase of the glucose signaling pathway directly regulates transcription by the yeast holoenzyme. In response to glucose limitation, the Snf1 kinase stimulates transcription by holoenzyme that has been artificially recruited to a reporter by a LexA fusion to a holoenzyme component. We show that Snf1 interacts physically with the Srb/mediator proteins of the holoenzyme in both two-hybrid and coimmunoprecipitation assays. We also show that a catalytically hyperactive Snf1, when bound to a promoter as a LexA fusion protein, activates transcription in a glucose-regulated manner; moreover, this activation depends on the integrity of the Srb/mediator complex. These results suggest that direct regulatory interactions between signal transduction pathways and RNA polymerase II holoenzyme provide a mechanism for transcriptional control in response to important signals.
Kuchin
S
S
Department of Genetics and Development and Department of Microbiology, Columbia University, New York, NY 10032, USA.
Treich
I
I
Carlson
M
M
D001426:Bacterial Proteins / Q000378:metabolism; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000494:pharmacology; D020035:Holoenzymes / Q000378:metabolism; D056892:Mediator Complex; D008957:Models, Genetic; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases; D016213:Cyclins; D005656:Fungal Proteins; D005947:Glucose; D020035:Holoenzymes; D056892:Mediator Complex; D017346:Protein Serine-Threonine Kinases; D012319:RNA Polymerase II; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases; D015534:Trans-Activators; D014157:Transcription Factors; D000099160:LexA Repressor Protein; C076878:SIN4 protein, S cerevisiae; C071570:SNF1-related protein kinases; C093345:SSN8 protein, S cerevisiae; C498309:SSN3 protein, S cerevisiae