Cyclic AMP receptor protein (CRP) regulates the expression of cspA, cspB, cspG and cspI, members of cspA family, in Escherichia coli.

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Escherichia coli K-12 contains nine paralogs of CspA, CspA-CspI, collectively known as CspA family of cold-shock proteins (CSPs). In spite of the high degree of similarity among themselves, only five (cspA, B, E, G and I) are induced during cold-stress. In the present study, we show that cspB, cspG and cspI, the members of cspA family, known to be induced in response to cold shock, are regulated by cyclic AMP receptor protein (CRP) , a global regulator involved in sugar metabolism, during growth at 37°C as well as at 15°C, as seen by green fluorescent protein (gfp) promoter fusions assays. Interestingly, cspA is selectively regulated by CRP during growth at 15°C but not at 37°C. The regulation of cspA, cspB, cspG and cspI by CRP was found to be through an indirect mechanism as determined by electrophoretic mobility shift assay (EMSA). These results substantiate our earlier study demonstrating a role for CRP during growth at low temperature.