PSEUDOMONAS-AERUGINOSA RFC GENES OF SEROTYPES O2 AND O5 COULD COMPLEMENT O-POLYMERASE-DEFICIENT SEMI-ROUGH MUTANTS OF EITHER SEROTYPE

Using a gene-replacement strategy and a mutated copy of the Pseudomona s aeruginosa O5 rfc gene, we were able to generate a rfc mutant in P. aeruginosa serotype O2. This mutant, which exhibits the semi-rough (SR ) LPS phenotype, was used to isolate the O2 rfc gene. Mobilization of the O2 and O5 rfc genes into SR mutants of the heterologous serotype r esulted in 'cross-polymerization' of O-repeat units, indicating that t he genes are functionally exchangeable. Analysis of the nucleotide seq uence of the rfc genes revealed that the two Rfc proteins are identica l. The results of this study have enabled us to propose the linkage ca talyzed by the O5 O-polymerase enzyme.