Genomewide transcriptional analysis of the cold shock response in Bacillus subtilis.

Previous studies with two-dimensional gel electrophoresis techniques revealed that the cold shock response in Bacillus subtilis is characterized by rapid induction and accumulation of two classes of specific proteins, which have been termed cold-induced proteins (CIPs) and cold acclimatization proteins (CAPs), respectively. Only recently, the B. subtilis two-component system encoded by the desKR operon has been demonstrated to be essential for the cold-induced expression of the lipid-modifying desaturase Des, which is required for efficient cold adaptation of the membrane in the absence of isoleucine. At present, one of the most intriguing questions in this research field is whether DesKR plays a global role in cold signal perception and transduction in B. subtilis. In this report, we present the first genomewide transcriptional analysis of a cold-exposed bacterium and demonstrate that the B. subtilis two-component system DesKR exclusively controls the desaturase gene des and is not the cold-triggered regulatory system of global relevance. In addition to this, we identified a set of genes that might participate as novel players in the cold shock adaptation of B. subtilis. Two cold-induced genes, the elongation factor homolog ylaG and the sigma(L)-dependent transcriptional activator homolog yplP, have been examined by construction and analysis of deletion mutants.