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This research investigates the role of the CsdA protein in E. coli under cold shock conditions.

January 9, 1996Proceedings of the National Academy of Sciences335 citationsOpen Access

Cold shock induces a major ribosomal-associated protein that unwinds double-stranded RNA in Escherichia coli.

PJPaula G. Jones MMMasanori Mitta YKY Kim

Key Points

This research investigates the role of the CsdA protein in E. coli under cold shock conditions.
Temperature shift from 37 to 15 degrees C to induce CsdA protein expression.
Isolation and characterization of CsdA localized to the ribosomal fraction.
Analysis of cell growth and protein synthesis post-csdA deletion.
CsdA became a major ribosomal-associated protein upon cold shock at 15 degrees C.
CsdA deletion significantly impaired cell growth and the synthesis of heat-shock proteins.
Purified CsdA unwound double-stranded RNA without the need for ATP.

Abstract

A 70-kDa protein was specifically induced in Escherichia coli when the culture temperature was shifted from 37 to 15 degrees C. The protein was identified to be the product of the deaD gene (reassigned csdA) encoding a DEAD-box protein. Furthermore, after the shift from 37 to 15 degrees C, CsdA was exclusively localized in the ribosomal fraction and became a major ribosomal-associated protein in cells grown at 15 degrees C. The csdA deletion significantly impaired cell growth and the synthesis of a number of proteins, specifically the derepression of heat-shock proteins, at low temperature. Purified CsdA was found to unwind double-stranded RNA in the absence of ATP. Therefore, the requirement for CsdA in derepression of heat-shock protein synthesis is a cold shock-induced function possibly mediated by destabilization of secondary structures previously identified in the rpoH mRNA.

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