Gln3-Gcn4 hybrid transcriptional activator determines catabolic and biosynthetic gene expression in the yeast Saccharomyces cerevisiae

► Gln3 and Gcn4 cooperatively activate catabolic and biosynthetic genes. ► Gln3 and Gcn4 can bind biosynthetic and catabolic promoters. ► Gln3 and Gcn4 constitute a hybrid transcriptional activator. ► Gln3-Gcn4 activator elicits peculiar transcriptional response.