Determination of RNA chaperone activity using an Escherichia coli mutant

Bacterial cold shock proteins (CSPs) function as RNA chaperones that destabilize RNA secondary structures. A quadruple mutant of Escherichia coli (cspA, cspB, cspG, and cspE) displays a cold-sensitive growth phenotype. Plant cold shock domain (CSD) proteins have been shown to complement the cold-sensitive phenotype of the E. coli mutant and to share a function with E. coli CSPs as RNA chaperones. This methodology, which is detailed here, can be utilized to reveal or probe the RNA chaperone activity of heterologous proteins.