Abstract
Cold shock domain (CSD) protein is widely distributed in bacteria, plants, and animals. The highly conserved CSD serves as a nucleic acid-binding domain for the functions in translational and/or transcriptional regulation. The cold shock (domain) proteins (Csp) from E. coli have a RNA chaperone activity. We have identified a cDNA encoding a CSD protein (WCSP1) from winter wheat. The cold-induced WCSP1 protein showed a nucleic acid binding activity and also complemented a cold sensitive phenotype of the E.coli csp mutant. To further investigate the function of WCSP1 in vitro, a molecular beacon system was utilized to demonstrate in vitro nucleic acid melting (unwinding) activity. The wild-type WCSP1 showed a nucleic acid melting activity, while the WCSP1 protein with point mutations in RNA-binding motifs were unable to do it. The data supported a function of WCSP1 in destabilizing RNA secondary structures during cold acclimation in wheat.
