title: RNA polymerase mutation activates the production of a dormant antibiotic 3,3'-neotrehalosadiamine via an autoinduction mechanism in Bacillus subtilis.
abstract: Bacillus and Streptomyces species possess the ability to produce a variety of commercially important metabolites and extracellular enzymes. We previously demonstrated that antibiotic production in Streptomyces coeli-color A3(2) and Streptomyces lividans can be enhanced by RNA polymerase (RNAP) mutations selected for the rifampicin-resistant (Rif(r)) phenotype. Here, we have shown that the introduction of a certain Rif(r) rpoB mutation into a B. subtilis strain resulted in cells that overproduce an aminosugar antibiotic 3,3'-neotrehalosadiamine (NTD), the production of which is dormant in the wild-type strain. Mutational and recombinant gene expression analyses have revealed a polycistronic gene ntdABC (formally yhjLKJ) and a monocistronic gene ntdR (formally yhjM) as the NTD biosynthesis operon and a positive regulator for ntdABC, respectively. Analysis of transcriptional fusions to a lacZ reporter revealed that NTD acts as an autoinducer for its own biosynthesis genes via NtdR protein. Our results also showed that the Rif(r) rpoB mutation causes an increase in the activity of sigma(A)-dependent promoters including ntdABC promoter. Therefore, we propose that unlike the wild-type RNAP, the mutant RNAP efficiently recognized the sigma(A)-dependent promoters, resulting in the dramatic activation of the NTD biosynthesis pathway by an autoinduction mechanism.
authors: Microbial Function Laboratory and Molecular Elucidation Laboratory, National Food Research Institute, Tsukuba, Ibaraki 305-8642, Japan.
authors: Takashi
authors: T
authors: Inaoka
authors: Kosaku
authors: K
authors: Takahashi
authors: Hiroshi
authors: H
authors: Yada
authors: Mitsuru
authors: M
authors: Yoshida
authors: Kozo
authors: K
authors: Ochi
mesh_terms: D000606:Amino Sugars / Q000737:chemistry / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000235:genetics*; D001483:Base Sequence; D015153:Blotting, Western; D004252:DNA Mutational Analysis; D004251:DNA Transposable Elements; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004926:Escherichia coli / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012293:Rifampin / Q000494:pharmacology; D012808:Sigma Factor / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic; D014199:Trehalose / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000606:Amino Sugars; D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D012808:Sigma Factor; C466027:trehalosamine; C049974:3,3'-neotrehalosadiamine; D014199:Trehalose; D012321:DNA-Directed RNA Polymerases; D012293:Rifampin