A transcriptional activator, homologous to the Bacillus subtilis PurR repressor, is required for expression of purine biosynthetic genes in Lactococcus lactis.

ABSTRACT: A purR::pGh9:ISS1 mutant of Lactococcus lactis was obtained following transposon mutagenesis of strain MG1363 and selection for purine auxotrophs. After determination of the nucleotide sequence and deduction of the purR reading frame, the PurR product was found to be highly similar to the purR-encoded repressor from Bacillus subtilis. The wild-type purR gene complemented the purine auxotrophy of a purR::ISS1 mutant, and it was shown that the purR::ISS1 mutation lowered the level of transcription from the purine-regulated L. lactis purD promoter. In a parallel study on the regulation of purC and purD expression in L. lactis (M. Kilstrup, S. G. Jessing, S. B. Wichmand-Jorgensen, M. Madsen, and D. Nilsson, J. Bacteriol. 180:3900-3906, 1998), we identified regions (PurBox sequences: AWWWCCGAAC

SUBMITTER: Kilstrup M 

PROVIDER: S-EPMC107375 | biostudies-literature | 1998 Aug

REPOSITORIES: biostudies-literature