RpoS-dependent expression of the second lysine decarboxylase gene in Escherichia coli

The second lysine decarboxylase gene (ldc) is at 4.7 min on the Escherichia coli chromosome [Kikuchi et al., J. Baceriol. 179, 4486-4492 (1997)]. This report showes that the expression of ldc as well as cadA was induced at stationary phase in the wild type of E. coli. The ldc was not expressed in a rpoS deletion mutant of E. coli at any growing stage. In contrast, cadA was expressed in the rpoS mutant. Thus, we conclude that the expression of ldc but not cadA at stationary phase is regulated by a RpoS-dependent mechanism (s) in E. coli.