NEWLY IDENTIFIED GENES INVOLVED IN THE SIGNAL-TRANSDUCTION OF ESCHERICHIA-COLI K-12

We cloned and sequenced two Escherichia coli genes which are members o f a family of an environmentally responsive two-component system. The nucleotide (nt) and deduced amino-acid sequences of these two genes we re found to be homologous to those of the Bordetella pertussis bvgA an d bvgS genes. They were mapped at 51 min (clones 6B9 to 7G9 of the Koh ara miniset library of the E. coli chromosome). Both proteins, deduced from their nt sequences, were identified in the coupled in vitro tran scription-translation system; their molecular masses were consistent w ith BvgA and BvgS (23 and 135 kDa, respectively). Furthermore, when th ese genes were expressed on a multicopy plasmid in an envZ deletion st rain, ompC expression was induced. This expression was found to be reg ulated by low temperature, MgSO4 and nicotinic acid, factors known to control the Virulence of B. pertussis via BvgA and BvgS. These results indicate that the newly cloned genes were structually and functionall y similar to bvgA and bvgS, and we designated these genes evgA and evg S.