Role of RNA structure and susceptibility to RNase E in regulation of a cold shock mRNA, cspA mRNA

Degradation of the cspA mRNA in vivo is very rapid at temperatures greater than 30[degrees]C and is moderately dependent on RNase E. Investigations in vitro show that degradosomes prepared from normal or cold-shocked cultures cleave the cspA mRNA preferentially at a single site in vitro between two stem-loops ~24 residues 3' to the termination codon and ~31 residues from the 3' end. The site of cleavage is independent of the temperature and largely independent of the phosphorylation status of the 5' end of cspA mRNA. A 5' stem-loop, potential occlusion of the initiation and termination codons, temperature-dependent translational efficiency, and the position of the RNase E cleavage site can explain the differential stability of the cspA mRNA.