MIG1 overexpression causes flocculation in Saccharomyces cerevisiae.
MIG1, encoding a C2H2 zinc-finger repressor protein involved in carbon catabolite repression, was found to play a role in non-sexual flocculation of Saccharomyces cerevisiae. Disruption of MIG1 in a flocculent mutant strain of NCYC 227, resulted in a non-flocculent phenotype. Expression of MIG1 on a 2 mu pRS426 vector in a non-flocculent strain, YM 4134, caused flocculation; MIG1 on a high-copy-number LEU2-d plasmid caused intense flocculation in the same strain. Mutations in the SSN6 and TUP1 genes confer a flocculent phenotype in non-flocculent strains of S. cerevisiae, and it has been shown that Mig1 can tether the Ssn6p-Tup1p complex to the regulatory regions of glucose-repressible genes. Mutations in tup1 in a MIG1 background caused flocculation while double mutants of TUP1 and MIG1 did not flocculate. Based on these results, a model for the role of MIG1 in flocculation gene regulation is proposed.
Shankar
C S
CS
Department of Food Microbiology, Central Food Technological Research Institute, Mysore, India.
Ramakrishnan
M S
MS
Umesh-Kumar
S
S
D015152:Blotting, Northern; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D005427:Flocculation; D005428:Flocculation Tests; D015966:Gene Expression Regulation, Fungal; D016296:Mutagenesis / Q000528:radiation effects; D016254:Mutagenesis, Insertional; D010957:Plasmids; D012333:RNA, Messenger / Q000302:isolation & purification; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; C085976:MIG1 protein, S cerevisiae; D012333:RNA, Messenger; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins