The XXXX metR gene encodes a bZIP protein which activates transcription of sulphur metabolism genes.

@entity462 @entity1255 @entity14940 @entity1853 @entity1980 @entity855 @entity597
The identification, isolation and characterization of a new @entity14940 positive-acting gene metR, which encodes a transcriptional activator of sulphur metabolism, is reported. metR mutants are tight auxotrophs requiring @entity1853 or @entity1255 for growth. Mutations in the metR gene are epistatic to mutations in the negative-acting sulphur regulatory scon genes. The metR coding sequence is interrupted by a single intron of 492 bp which is unusually long for fungi. @entity14940 METR is a member of bZIP family of DNA-binding proteins. The bZIP domains of METR and the @entity1980 CYS3 transcriptional activator of sulphur genes are highly similar. Although @entity1980 cys-3 gene does not substitute for the metR function, a chimeric metR gene with a cys-3 bZIP domain is able to transform the DeltametR mutant to @entity1853 prototrophy. This indicates that METR recognizes the same regulatory sequence as CYS3. The metR gene is not essential, as deletion mutants are viable and have similar phenotype as point mutants. In contrast to the @entity1980 cys-3, transcription of the metR gene was found to be regulated neither by METR protein nor by sulphur source. Transcription of metR gene is derepressed in the sconB2 mutant. Transcription of genes encoding @entity597 permease, @entity1255 synthase, @entity462 synthase, @entity855 -sulphurylase, and sulphur controller--sconB is strongly regulated by the metR gene product and depends on the character of the metR mutation and sulphur supplementation.
