Complete growth inhibition of Escherichia coli by ribosome trapping with truncated cspA mRNA at low temperature

Abstract

Background: CspA, the major cold‐shock protein of Escherichia coli, is transiently induced upon temperature downshift and considered to play an important role in low‐temperature adaptation. Results: Overproduction of truncated cspA mRNAs retaining translational ability was found to completely block cell growth at low temperatures. This effect was termed ‘low‐temperature antibiotic effect of truncated cspA expression (LACE)’. In contrast to the significant reduction of polysomes in normal cells upon cold shock, cells under LACE maintained a high polysome profile, producing only truncated cspA products. Growth inhibition of cells under LACE was suppressed when CspA was overproduced together with the truncated cspA mRNA. Conclusion: LACE is caused by the overproduction of a truncated cspA mRNA in the absence of CspA production, which in turn traps all the cellular ribosomes in a non‐adaptive form incapable of forming initiation complexes with other cellular mRNAs. LACE may provide a novel approach to the development of a new antibiotic.