MOLECULAR-GENETIC ANALYSIS OF TYPE-4 PILUS BIOGENESIS AND TWITCHING MOTILITY USING PSEUDOMONAS-AERUGINOSA AS A MODEL SYSTEM - A REVIEW

Genetic analysis of Pseudomonas aeruginosa pilus biogenesis and twitch ing motility has revealed the requirement for several pil loci which h ave been localized to different regions of the chromosome. One pil loc us, designated pilE, resides at approx. 71 min on the PAO genetic map, a region of the chromosome previously shown to harbor a number of gen es required for pilus assembly (i.e., pilA, -B, -C, -D, -R and -S). Th e PilE protein shows significant sequence identity to the N-terminal d omain of PilA as well as to the pilin precursors from a variety of typ e-4 pilus producers. Included within this homologous region is a short , positively charged leader sequence followed by a prepilin peptidase cleavage site and a largely hydrophobic region. Additionally, an unlin ked set of pil genes, designated pilG, -H, -I, -J and -K, has been loc alized to the SpeI fragment H which corresponds to approx. 20 min on t he PAO genetic map. This gene cluster encodes proteins that demonstrat e remarkable similarity to the chemotaxis proteins of enterics and the gliding bacterium Myxococcus xanthus and are thought to be part of a signal transduction system that controls P. aeruginosa pilus biosynthe sis and twitching motility. (C) 1997 Elsevier Science B.V.