CabC, an EF-hand calcium-binding protein, is involved in Ca2+-mediated regulation of spore germination and aerial hypha formation in Streptomyces coelicolor.
Ca(2+) was reported to regulate spore germination and aerial hypha formation in streptomycetes; the underlying mechanism of this regulation is not known. cabC, a gene encoding an EF-hand calcium-binding protein, was disrupted or overexpressed in Streptomyces coelicolor M145. On R5- agar, the disruption of cabC resulted in denser aerial hyphae with more short branches, swollen hyphal tips, and early-germinating spores on the spore chain, while cabC overexpression significantly delayed development. Manipulation of the Ca(2+) concentration in R5- agar could reverse the phenotypes of cabC disruption or overexpression mutants and mimic mutant phenotypes with M145, suggesting that the mutant phenotypes were due to changes in the intracellular Ca(2+) concentration. CabC expression was strongly activated in aerial hyphae, as determined by Western blotting against CabC and confocal laser scanning microscopy detection of CabC::enhanced green fluorescent protein (EGFP). CabC::EGFP fusion proteins were evenly distributed in substrate mycelia, aerial mycelia, and spores. Taken together, these results demonstrate that CabC is involved in Ca(2+)-mediated regulation of spore germination and aerial hypha formation in S. coelicolor. CabC most likely acts as a Ca(2+) buffer and exerts its regulatory effects by controlling the intracellular Ca(2+) concentration.
Wang
Sheng-Lan
SL
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
Fan
Ke-Qiang
KQ
Yang
Xu
X
Lin
Zeng-Xi
ZX
Xu
Xin-Ping
XP
Yang
Ke-Qian
KQ
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D025301:Hyphae / Q000254:growth & development*; D008969:Molecular Sequence Data; D010641:Phenotype; D016415:Sequence Alignment; D013171:Spores, Bacterial / Q000502:physiology; D048372:Streptomyces coelicolor / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D002118:Calcium