Interaction of the GATA factor Gln3p with the nitrogen regulator Ure2p in Saccharomyces cerevisiae

We used cells carrying plasmids causing the overproduction of Gln3p, Ure2p, or both of these proteins to elucidate the ability of Ure2p to prevent the activation of gene expression by Gln3p in cells growing in a glutamine-containing medium. Our results indicate that Ure2p probably does not interfere with the binding of the GATA factor Gln3p to GATAAG sites but acts directly on Gln3p to block its ability to activate transcription.