title: Repression by SSN6-TUP1 is directed by MIG1, a repressor/activator protein.
abstract: The SSN6-TUP1 protein complex represses transcription of diversely regulated genes in the yeast Saccharomyces cerevisiae. Here we present evidence that MIG1, a zinc-finger protein in the EGR1/Zif268 family, recruits SSN6-TUP1 to glucose-repressed promoters. DNA-bound LexA-MIG1 represses transcription of a target gene in glucose-grown cells, and repression requires SSN6 and TUP1. We also show that MIG1 and SSN6 fusion proteins interact in the two-hybrid system. Unexpectedly, we found that LexA-MIG1 activates transcription strongly in an ssn6 mutant and weakly in a tup1 mutant. Finally, LexA-MIG1 does not repress transcription in glucose-deprived cells, and MIG1 is differentially phosphorylated in response to glucose availability. We suggest a role for phosphorylation in regulating repression.
authors.affiliation: Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Treitel
authors.forename: M
authors.initials: M
authors.lastname: Carlson
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010766:Phosphorylation; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases; D014158:Transcription, Genetic; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D005947:Glucose; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C065455:CYC8 protein, S cerevisiae; C085976:MIG1 protein, S cerevisiae; C066502:TUP1 protein, S cerevisiae