Isolation of the MIG1 gene from Candida albicans and effects of its disruption on catabolite repression

We have cloned a Candida albicans gene (CaMIG1) that encodes a protein homo logous to the DNA-binding protein Mig1 from Saccharomyces cerevisiae (ScMig 1). The C. albicans Mig1 protein (CaMig1) differs from ScMig1, in that, amo ng other things, it lacks a putative phosphorylation site for Snf1 and pres ents several long stretches rich in glutamine or in asparagine, serine, and threonine and has the effector domain located at some distance (50 amino a cids) from the carboxy terminus. Expression of CaMIG1 was loa and was simil ar in glucose-, sucrose-, or ethanol-containing media, Disruption of the tw o CaMIG1 genomic copies had no effect in filamentation or infectivity, Leve ls of a glucose-repressible alpha-glucosidase, implicated in both sucrose a nd maltose utilization, were similar in wild-type or mig1/mig1 cells, Disru ption of CaMIG1 had also no effect on the expression of the glucose-repress ed gene CaGAL1. CaMIG1 was functional in S. cerevisiae, as judged by its ab ility to suppress the phenotypes produced by mig1 or tps1 mutations. In add ition, CaMig1 formed specific complexes with the URS1 region of the S, cere visiae FBP1 gene, The existence of a possible functional analogue of CaMIG1 in C. albicans was suggested by the results of band shift experiments.