A REGULATORY GENE (CCAR) REQUIRED FOR CEPHAMYCIN AND CLAVULANIC ACID PRODUCTION IN STREPTOMYCES-CLAVULIGERUS - AMPLIFICATION RESULTS IN OVERPRODUCTION OF BOTH BETA-LACTAM COMPOUNDS
Fj. Perezllarena et al., A REGULATORY GENE (CCAR) REQUIRED FOR CEPHAMYCIN AND CLAVULANIC ACID PRODUCTION IN STREPTOMYCES-CLAVULIGERUS - AMPLIFICATION RESULTS IN OVERPRODUCTION OF BOTH BETA-LACTAM COMPOUNDS, Journal of bacteriology, 179(6), 1997, pp. 2053-2059
A regulatory gene (ccaR), located within the cephamycin gene cluster o
f Streptomyces clavuligerus, is linked to a gene (blp) encoding a prot
ein similar to a beta-lactamase-inhibitory protein. Expression of ccaR
is required for cephamycin and clavulanic acid biosynthesis in S. cla
vuligerus. The ccaR-encoded protein resembles the ActII-ORB4, RedD, Af
sR, and DnrI regulatory proteins of other Streptomyces species, all of
which share several motifs, Disruption of ccaR by targeted double rec
ombination resulted in the loss of the ability to synthesize cephamyci
n and clavulanic acid. Complementation of the disrupted mutant with cc
aR restored production of both secondary metabolites. ccaR was express
ed as a monocistronic transcript at 24 and 48 h in S. clavuligerus cul
tures (preceding the phase of antibiotic accumulation), but no transcr
ipt hybridization signals were observed at 72 or 96 h. This expression
pattern is consistent with those of regulatory proteins required for
antibiotic biosynthesis. Amplification of ccaR in S. clavuligerus resu
lted in a two- to threefold increase in the production of cephamycin a
nd clavulanic acid.