title: Identification of two genes with prepilin-like leader sequences involved in type 4 fimbrial biogenesis in Pseudomonas aeruginosa.
abstract: Type 4 fimbriae are surface filaments produced by a range of bacterial pathogens for colonization of host epithelial surfaces. In Pseudomonas aeruginosa, they are involved in adhesion as well as in a form of surface translocation called twitching motility, and sensitivity to infection by fimbria-specific bacteriophage. Analysis of the 2.5-kb intergenic region between the previously defined pilR and pilV genes on P. aeruginosa genomic SpeI fragment E has identified three new genes, fimT, fimU, and dadA*. The predicted 18.5-kDa products of the fimT and fimU genes contain prepilin-like leader sequences, whereas the third gene, dadA*, encodes a protein similar to the D-amino acid dehydrogenase of Escherichia coli. Isogenic mutants constructed by allelic exchange demonstrated that the fimU gene was required for fimbrial biogenesis and twitching motility, whereas the fimT and dada* mutants retained wild-type phenotypes. However, overexpression of the fimT gene was found to be able to functionally replace the lack of a fimU gene product, suggesting a subtle role in fimbrial biogenesis. The identification of these proteins increases the similarity between type 4 fimbrial biogenesis and the supersystems involved in macromolecular traffic, such as extracellular protein secretion and DNA uptake, all of which now possess multiple protein species that possess prepilin-like leader sequences.
authors.affiliation: Centre for Molecular and Cellular Biology, The University of Queensland, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Alm
authors.forename: J S
authors.initials: JS
authors.lastname: Mattick
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics*; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D011498:Protein Precursors / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C077573:PilV protein, Bacteria; D011498:Protein Precursors; D021382:Protein Sorting Signals; D014157:Transcription Factors; C074774:pilR protein, Pseudomonas aeruginosa; D036781:Fimbriae Proteins