Résumé
Transposon mutagenesis of Bacillus cereus ATCC 14579 yielded cold-sensitive mutants. Mutants of genes encoding enzymes of the central metabolism were affected by cold, but also by other stresses, such as pH or salt, whereas a mutant with transposon insertion in the promoter region of BC0259 gene, encoding a putative DEAD-box RNA helicase displaying homology with Escherichia coli CsdA and Bacillus subtilis CshA RNA helicases, was only cold-sensitive. Expression of the BC0259 gene at 10 degrees C is reduced in the mutant. Analysis of the 5' untranslated region revealed the transcriptional start and putative cold shock-responsive elements. The role of this RNA helicase in the cold-adaptive response of B. cereus is discussed.