Rational elicitation of cold-sensitive phenotypes.

Cold-sensitive phenotypes have helped us understand macromolecular assembly and biological phenomena, yet few attempts have been made to understand the basis of cold sensitivity or to elicit it by design. We report a method for rational design of cold-sensitive phenotypes. The method involves generation of partial loss-of-function mutants, at either buried or functional sites, coupled with selective overexpression strategies. The only essential input is amino acid sequence, although available structural information can be used as well. The method has been used to elicit cold-sensitive mutants of a variety of proteins, both monomeric and dimeric, and in multiple organisms, namely Escherichia coli, Saccharomyces cerevisiae, and Drosophila melanogaster This simple, yet effective technique of inducing cold sensitivity eliminates the need for complex mutations and provides a plausible molecular mechanism for eliciting cold-sensitive phenotypes.