QUTR (qutR-encoded transcription-repressing protein) is a multi-domain repressor protein active in the signal-transduction pathway that regulates transcription of the quinic acid utilization (qut) gene cluster in Aspergillus nidulans. In the presence of quinate, production of mRNA from the eight genes of the qut pathway is stimulated by the activator protein QUTA (qutA-encoded transcription-activating protein). Mutations in the qutR gene alter QUTR function such that the transcription of the qut gene cluster is permanently on (constitutive phenotype) or is insensitive to the presence of quinate (super-repressed phenotype). These mutant phenotypes imply that the QUTR protein plays a key role in signal recognition and transduction, and we have used deletion analysis to determine which regions of the QUTR protein are involved in these functions. We show that the QUTR protein recognizes and binds to the QUTA protein in vitro and that the N-terminal 88 amino acids of QUTR are sufficient to inactivate QUTA function in vivo. Deletion analysis and domain-swap experiments imply that the two C-terminal domains of QUTR are mainly involved in signal recognition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.