Characterization of a novel two-component regulatory system involved in the regulation of both actinorhodin and a type I polyketide in Streptomyces coelicolor.
To seek more information on function of two-component regulatory systems (TCSs) in Streptomyces coelicolor, a dozen TCS-knockout mutants were generated, and phenotype changes were determined. One TCS (SCO5403/5404)-deleted mutant with phenotype change was obtained. Here, we report the characterization of this novel TCS, designated as RapA1/A2 (regulation of both actinorhodin and a type I polyketide), using genetic and proteomic approaches. Although growth and morphological analyses showed no difference between the knockout mutant and wild-type strain M145, a visible decrease of the production of actinorhodin (Act) was observed in rapA1/A2 mutant. The decrease can be restored by introducing rapA1/A2 genes on an integrative vector. A 2D-gel based proteomic analysis showed that knockout of rapA1/A2 resulted in reduced expression of a putative 3-oxoacyl-[acyl-carrier protein] reductase that is part of a biosynthetic cluster for a cryptic type I polyketide. Further reverse-transcriptase-polymerase chain reaction (RT-PCR) analyses confirmed that expression levels of several biosynthetic genes and the respective pathway-specific regulatory genes actII-ORF4 and kasO for these two clusters were all down-regulated in the rapA1/A2 mutant, compared to M145. Taken together, the results demonstrated that RapA1/A2 may serve as a positive regulator for biosynthesis of both Act and the uncharacterized polyketide in S. coelicolor, and the effects exerted by RapA1/A2 were dependent on the pathway-specific regulatory genes.
Lu
Yinhua
Y
Laboratory of Molecular Microbiology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, People's Republic of China.
Wang
Weihua
W
Shu
Dan
D
Zhang
Weiwen
W
Chen
Lei
L
Qin
Zhongjun
Z
Yang
Sheng
S
Jiang
Weihong
W
D000880:Anthraquinones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D050505:Mutant Proteins / Q000096:biosynthesis / Q000235:genetics; D048630:Polyketide Synthases / Q000235:genetics* / Q000378:metabolism; D020543:Proteome; D048372:Streptomyces coelicolor / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000095622:Benzoisochromanequinones
D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D050505:Mutant Proteins; D048630:Polyketide Synthases; D020543:Proteome; C013390:actinorhodin; D000095622:Benzoisochromanequinones