Cloning and sequencing of the gene encoding the RpoS (KatF) sigma factor from Salmonella typhimurium 14028s

The gene encoding the alternative sigma factor RpoS in Salmonella typhimurium was cloned by its ability to complement acid susceptibility in rpoS mutant Escherichia coli. Sequence determination and comparison with rpoS from E. coli demonstrates a high degree of conservation, although significant differences are found within the extragenic regulatory regions.