PILO, A GENE REQUIRED FOR GLYCOSYLATION OF PSEUDOMONAS-AERUGINOSA-1244 PILIN

Nucleotide sequencing of a region downstream from the Pseudomonas aeruginosa 1244 pilin structural gene, pilA, revealed an ORF potentially able to code for a protein of M(r) 50862. This ORF, called pilO, was flanked by a tRNA(thr) gene, which was followed by a transcriptional termination sequence, The tRNA(thr) gene and the termination sequence were nearly identical to sequences found immediately adjacent to the pilA gene of several P. aeruginosa strains. A 2200 base mRNA strand, which contained both the pilO and pilA transcripts, was produced from this region, while a 650 base transcript containing only pilA was present in a 100-fold excess over the longer transcript. Hyperexpression of the pilA gene in a PilO(-) strain resulted in normal pilus-specific phage sensitivity and twitching motility. The pilin produced by this strain had a lower apparent M(r) and a more neutral pi compared to that produced by a strain containing a functional pilO gene. This pilin failed to react with a sugar-specific reagent which recognized pilin produced by the strain containing a functional pilO gene.