Role for Vitamin B12 in Light Induction of Gene Expression in the Bacterium Myxococcus xanthus
AUTOR(ES)
Cervantes, María
FONTE
American Society for Microbiology
RESUMO
A light-inducible promoter (PB) drives the carB operon (carotenoid genes) of the bacterium Myxococcus xanthus. A gene encoding a regulator of carotenoid biosynthesis was identified by studying mutant strains carrying a transcriptional fusion to PB and deletions in three candidate genes. Our results prove that the identified gene, named carA, codes for a repressor of the PB promoter in the dark. They also show that the carA gene product does not participate in the light activation of two other promoters connected with carotenoid synthesis or its regulation in M. xanthus. CarA is a novel protein consisting of a DNA-binding domain of the family of MerR helix-turn-helix transcriptional regulators, directly joined to a cobalamin-binding domain. In support of this, we report here that the presence of vitamin B12 or some other cobalamin derivatives is absolutely required for activation of the PB promoter by light.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=134944Documentos Relacionados
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