RT Journal Article SR Electronic(1) A1 Anderson, Todd A1 Brian, Paul A1 Riggle, Perry A1 Kong, Renqiu A1 Champness, Wendy YR 1999 T1 Genetic suppression analysis of non-antibiotic-producing mutants of the Streptomyces coelicolor absA locus JF Microbiology, VO 145 IS 9 SP 2343 OP 2353 DO https://doi.org/10.1099/00221287-145-9-2343 PB Microbiology Society, SN 1465-2080, AB The absA locus in Streptomyces coelicolor A3(2) was identified because mutations in it uncoupled sporulation from antibiotic synthesis: absA mutants failed to produce any of the four antibiotics characteristic of S. coelicolor. These mutants are now shown to contain point mutations in the absA1 gene which encodes the histidine kinase sensor-transmitter protein of a two-component signalling system. The absA1 non-antibiotic-producing mutants, which are unpigmented, spontaneously acquire pigmented colony sectors. Genetic analysis established that the pigmented sectors contain second-site suppressive mutations, sab (for suppressor of ab s). Phenotypic characterization showed that sab strains produce all four antibiotics; some overproduce antibiotics and are designated Pha, for precocious hyperproduction of antibiotics. A set of sab mutations responsible for suppression was localized by plasmid-mediated and protoplast fusion mapping techniques to the vicinity of the absA locus. DNA cloned from this region was used to construct phage that could transduce sab mutations. Sequence analysis of sab strains defined sab mutations in both the absA1 gene and the absA2 gene; the latter encodes the two-component system’s response regulator., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-145-9-2343