P. Brian et al., GLOBAL NEGATIVE REGULATION OF STREPTOMYCES-COELICOLOR ANTIBIOTIC-SYNTHESIS MEDIATED BY AN ABSA-ENCODED PUTATIVE SIGNAL-TRANSDUCTION SYSTEM, Journal of bacteriology, 178(11), 1996, pp. 3221-3231
Streptomycete antibiotic synthesis is coupled to morphological differe
ntiation such that antibiotics are produced as a colony sporulates. St
reptomyces coelicolor produces several structurally and genetically di
stinct antibiotics. The S. coelicolor absA locus was defined by four U
V-induced mutations that globally blocked antibiotic biosynthesis with
out blocking morphological differentiation. We show that the absA locu
s encodes a putative eubacterial two-component sensor kinase-response
regulator system. All four mutations lie within a single open reading
frame, designated absA1, which is predicted to encode a sensor histidi
ne kinase. A second gene downstream of absA1, absA2, is predicted to e
ncode the cognate response regulator. In marked contrast to the antibi
otic-deficient phenotype of the previously described absA mutants, the
phenotype caused by disruption mutations in the absA locus is precoci
ous hyperproduction of the antibiotics actinorhodin and undecylprodigi
osin. Precocious hyperproduction of these antibiotics is correlated wi
th premature expression of XylE activity in a transcriptional fusion t
o an actinorhodin biosynthetic gene. We propose that the absA locus en
codes a Signal transduction mechanism that negatively regulates synthe
sis of the multiple antibiotics produced by S. coelicolor.