Identification of a novel gene, fimV, involved in twitching motility in Pseudomonas aeruginosa The GenBank accession number for the sequence determined in this work is U93274.

Abstract

Transposon mutagenesis was used to identify a new locus required for twitching motility in Pseudomonas aeruginosa. Four Tn5-B21 mutants which lacked twitching motility and a fifth which exhibited impaired motility were found to map to the same KpnI restriction fragment at approximately 40 min on the P. aeruginosa genome. Cloning and sequencing studies showed that all five transposon insertions occurred within the same 28 kb ORF, which was termed fimV. The product of this gene has a putative peptidoglycan-binding domain, predicted transmembrane domains, a highly acidic C terminus and anomalous electrophoretic migration, indicating unusual primary or secondary structure. The P. aeruginosa genome also possesses a paralogue of fimV. Homologues of fimV were also found in the sequenced genomes of the other type-IV-fimbriated bacteria Neisseria gonorrhoeae, Neisseria meningitidis, Legionella pneumophila and Vibrio cholerae, but not in those of other bacteria which lack type IV fimbriae. A fimV homologue was also found in the genome sequence of Shewanella putrefaciens, along with many other homologues of type IV fimbrial genes, indicating that this bacterium is also likely to produce type IV fimbriae. Wild-type twitching motility was restored to fimV mutants by complementation in a dosage-dependent manner. Overexpression of fimV resulted in an unusual phenotype where the cells were massively elongated and migrated in large convoys at the periphery of the colony. It is suggested that FimV may be involved in remodelling of the peptidoglycan layer to enable assembly of the type IV fimbrial structure and machinery.

The truA gene of Pseudomonas aeruginosa is required for the expression of type III secretory genes

“…The fimV mutant grew as well as wild-type PAK in L broth with (type III inducing condition) or without 5 mM EGTA. As reported by Semmler et al (2000), the fimV mutant was completely defective in twitching motility (Fig. 1), although type IV pili were observed on the surface by scanning electron microscopy.…”

“…cyaA encodes a protein that shares 54 % similarity with adenylate cyclase of E. coli (Aiba et al, 1983) and was recently reported to be essential for efficient expression of the type III genes in response to the low-calcium signal (Wolfgang et al, 2003); thus its effect on cell lifting is understandable. FimV is a twitching motility protein (Semmler et al, 2000) and PilL is a probable component of the chemotactic signal transduction system, with its C-terminal half showing 51 % similarity to chemotaxis protein CheA of Synechocystis sp. (Mattick et al, 1996); thus twitching motility might affect the type III secretion as previously suggested (Comolli et al, 1999, Kang et al, 1997.…”

Role of fimV in type II secretion system-dependent protein secretion of Pseudomonas aeruginosa on solid medium

“…uk) which is thought to have a general peptidoglycan binding function and to be present in a variety of enzymes involved in bacterial cell degradation (Interpro entry IPR018392). As FimV has been shown to be involved in type IV pilus assembly (Semmler et al, 2000), one could imagine that the loss of FimV affects a peptidoglycan breaching step necessary for pilus assembly. It could also be possible that the same peptidoglycan breaching mechanism is required for assembly of the T2SS machinery.…”

“…The former gene encodes a well-known global regulator that controls several processes (expression of genes encoding proteases, exotoxin A, twitching motility and QS) (Albus et al, 1997;Beatson et al, 2002;Suh et al, 2002;Kanack et al, 2006;Fox et al, 2008) and the latter encodes a protein involved in type IV pili assembly but has been poorly studied so far (Semmler et al, 2000;Ahn et al, 2004). Both genes were also reported to be required for twitching motility and indeed, as expected, we observed that the selected mutants were impaired for this movement mode (data not shown).…”

Heteroorganic molecules and bacterial biofilms: Controlling biodeterioration of cultural heritage

“…141 These 'rafts' or 'trails' of cells move radially outwards, always in cell-to-cell contact, leading to a dynamic lattice-like network (Figure 4). 141,144 Biofilm formation ensues once a mature lattice with less motile cells and a higher three dimensionality begins to develop.…”