GTS1 induction causes derepression of Tup1-Cyc8-repressing genes and chromatin remodeling through the interaction of Gts1p with Cyc8p.

GTS1 in yeast Saccharomyces cerevisiae is a pleiotropic gene, the expression of which affects a wide range of biological phenomena. A genome-wide transcriptional analysis identified genes upregulated in response to GTS1 induction, most of which were found to be regulated by the Tup1-Cyc8 co-repressor. Among the upregulated genes, FLO1 was indispensable for cell aggregation, one of the pleiotropic effects of GTS1. Deletion of genes encoding the chromatin remodeling complex SWI/SNF abolished FLO1 upregulation and decreased cell aggregation, although the nuclear localization of Gts1p required for cell aggregation was not affected. GTS1 induction caused chromatin remodeling at the FLO1 promoter in a SWI/SNF-dependent manner on micrococcal nuclease accessibility assay. Cyc8p was detected in Gts1p-mediated protein aggregates by agarose gel electrophoresis, indicating that Gts1p inhibited Cyc8p function. These results suggest that inhibition of the Tup1-Cyc8 complex and subsequent SWI/SNF-dependent chromatin remodeling result in Gts1p-mediated gene derepression.