Q pili enhance the attachment of <i>Moraxella bovis</i> to bovine corneas <i>in vitro</i>

Ruehl, William W.; Marrs, Carl F.; Beard, M.K. McG.; Shokooki, V.; Hinojoza, Julian R.; Banks, S.; Bieber, David; Mattick, John S.

doi:10.1111/j.1365-2958.1993.tb01119.x

Cited by 48 publications

(26 citation statements)

References 20 publications

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“…Further sequence analysis revealed that a 26-bp region including the sequence encoding the first 6 amino acids of PilQ was responsible for inversion of the pilin genes and subsequent expression of the leading gene (148). The Q pilin is associated with increased binding to corneal tissue compared with the I pilin (337). Recent studies of Moraxella catarrhalis, an emerging human pathogen responsible for a large proportion of otitis media and other upper respiratory tract infections, showed a low level of pilin diversity (262).…”

Section: Moraxella and Dichelobacter Pilin Diversitymentioning

confidence: 99%

Type IV Pilin Proteins: Versatile Molecular Modules

Giltner

Nguyen

Burrows

2012

Microbiol Mol Biol Rev

386

519

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SUMMARYType IV pili (T4P) are multifunctional protein fibers produced on the surfaces of a wide variety of bacteria and archaea. The major subunit of T4P is the type IV pilin, and structurally related proteins are found as components of the type II secretion (T2S) system, where they are called pseudopilins; of DNA uptake/competence systems in both Gram-negative and Gram-positive species; and of flagella, pili, and sugar-binding systems in the archaea. This broad distribution of a single protein family implies both a common evolutionary origin and a highly adaptable functional plan. The type IV pilin is a remarkably versatile architectural module that has been adopted widely for a variety of functions, including motility, attachment to chemically diverse surfaces, electrical conductance, acquisition of DNA, and secretion of a broad range of structurally distinct protein substrates. In this review, we consider recent advances in this research area, from structural revelations to insights into diversity, posttranslational modifications, regulation, and function.

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Section: Moraxella and Dichelobacter Pilin Diversitymentioning

confidence: 99%

Type IV Pilin Proteins: Versatile Molecular Modules

Giltner

Nguyen

Burrows

2012

Microbiol Mol Biol Rev

386

519

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“…bovis exhibits antigenic and phase variations of its type 4 pili, alternately expressing Q-or I-type pili and switching between P ϩ (piliated) and P Ϫ (nonpiliated) at a frequency as high as 10 Ϫ4 per cell per generation (21). M. bovis cells expressing Q-type pili are more efficient at establishing infection than those expressing I-type pili (27,29), and nonpiliated M. bovis cells cannot establish infection (15). Therefore, pili are important virulence factors.…”

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confidence: 99%

Transcriptional regulation of type 4 pilin genes and the site-specific recombinase gene, piv, in Moraxella lacunata and Moraxella bovis

Heinrich

Glasgow

1997

J Bacteriol

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Moraxella lacunata and Moraxella bovis use type 4 pili to adhere to epithelial tissues of the cornea and conjunctiva. Primer extension analyses were used to map the transcriptional start sites for the genes encoding the major pilin subunits (tfpQ/I) and the DNA invertase (piv), which determines pilin type expression. tfpQ/I transcription starts at a 54 -dependent promoter (tfpQ/Ip 2 ) and, under certain growth conditions, this transcription is accompanied by weaker upstream transcription that starts at a potential 70 -dependent promoter (tfpQ/Ip 1 ). piv is expressed in both M. lacunata and M. bovis from a putative 70 -dependent promoter (pivp) under all conditions assayed. 54 -dependent promoters require activators in order to initiate transcription; therefore, it is likely that tfpQ/Ip 2 is also regulated by an activator in Moraxella. Primer extension assays with RNA isolated from Escherichia coli containing the subcloned pilin inversion region from M. lacunata showed that pivp is used for the expression of piv; however, tfpQ/Ip 2 is not used for the transcription of tfpQ/I. Transcription from tfpQ/Ip 2 was activated in E. coli when the sensor (PilS) and response regulator (PilR) proteins of type 4 pilin transcription in Pseudomonas aeruginosa were expressed from a plasmid. These results suggest that the expression of the type 4 pilin in M. lacunata and M. bovis is regulated not only by a site-specific DNA inversion system but also by a regulatory system which is functionally analogous to the PilS-PilR two-component system of P. aeruginosa.Moraxella lacunata and Moraxella bovis are gram-negative human and bovine pathogens, respectively, that primarily infect the conjunctiva and cornea (3,15,29,32). Attachment to the epithelial tissues of these areas is mediated by type 4 pili (28). Other bacteria that express type 4 pili include Neisseria gonorrhoeae, Neisseria meningitidis, Pseudomonas aeruginosa, Vibrio cholerae, Aeromonas hydrophila, and Dichelobacter nodosus (10,13,23,25,37). In bacteria expressing type 4 pili, the major pilin subunit is expressed as a pre-pilin protein with an unusually short 6-amino-acid leader sequence followed by a predominantly hydrophobic domain (35). The hydrophobic domain and the leader sequence are required to deliver the protein to an ATP-dependent, Sec-independent secretory pathway (34). During the process of secretion, a pre-pilin peptidase cleaves the leader sequence and methylates the first amino acid of the mature protein, creating N-methylphenylalanine (36). Thus, type 4 pili have also been classified as MePhe pili.M. bovis exhibits antigenic and phase variations of its type 4 pili, alternately expressing Q-or I-type pili and switching between P ϩ (piliated) and P Ϫ (nonpiliated) at a frequency as high as 10 Ϫ4 per cell per generation (21). M. bovis cells expressing Q-type pili are more efficient at establishing infection than those expressing I-type pili (27, 29), and nonpiliated M. bovis cells cannot establish infection (15). Therefore, pili are important virulence factor...

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“…Both of these gram-negative pathogens produce type 4 (MePhe) pili, which are important virulence factors mediating adherence of the bacilli to corneal tissue (7,22,23,29). M. bovis and M. lacunata utilize site-specific DNA inversion of a chromosomal segment to alter the expression of their type 4 pilin genes (22, 28).…”

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confidence: 99%

Amino acid sequence homology between Piv, an essential protein in site-specific DNA inversion in Moraxella lacunata, and transposases of an unusual family of insertion elements

Lenich

Glasgow

1994

J Bacteriol

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Deletion analysis of the subcloned DNA inversion region of MoraxeUla lacunata indicates that Piv is the only M. lacunata-encoded factor required for site-specific inversion of the tlpQIip'I pilin segment. The predicted amino acid sequence of Piv shows significant homology solely with the transposases/integrases of a family of insertion sequence elements, suggesting that Piv is a novel site-specific recombinase.Moraxella lacunata and Moraxella bovis are human and bovine ocular pathogens, respectively (4,17,27). Both of these gram-negative pathogens produce type 4 (MePhe) pili, which are important virulence factors mediating adherence of the bacilli to corneal tissue (7,22,23,29). M. bovis and M. lacunata utilize site-specific DNA inversion of a chromosomal segment to alter the expression of their type 4 pilin genes (22, 28). M. bovis alternately expresses Q and I pilin, and M. lacunata apparently exhibits an on/off pilin phase variation (23, 30). The 2.1-kb invertible DNA segment in M. bovis contains the carboxyl-terminal portion of the tfpQ and tfpI pilin genes and an additional open reading frame, ORF1 or tfpB ( Fig. 1) (21).The promoter and constant region of the pilin genes is located upstream of the invertible segment. The DNA inversion region of M. lacunata is very similar in sequence and organization to that of M. bovis, with the notable exceptions of a 19-bp duplication within the coding sequence for the carboxylterminal region of the tfpI pilin gene, resulting in no active pilin expression in one orientation of the invertible segment, and a 2-bp deletion in tfpB which shortens the ORF by one-third (28).A subcloned 6-kb fragment containing the inversion region of M. lacunata in a pBluescript vector (pMxLl; Fig. 1 (22), has the inversion region from M. lacunata (same region encoded on pMxLl), but piv has been inactivated by insertion of a segment from the fl interposon encoding streptomycin/spectinomycin resistance. The deletion of tfpB was accomplished by restriction of pMxL5 with AfllI and SnaBI (New England Biolabs) (Fig. 1) and ligation of the annealed oligonucleotides 5'-TTAAGATCGATGACGTCAGATCTG AGCTCGATACTCGAG-3' and 5'-CTCGAGTATCGAGCT CAGATCT'GACGTCATCGATC-3' into the Aflll and SnaBI sites, using T4 DNA ligase (Boehringer) to create pAG701. Inversion assays were then performed by transforming E. coli DH5a containing pMxL5 or pAG701 with a compatible plasmid, pACYCpiv-1 (provided by Meredith Hackel and Carl Marrs), which is pACYC184 containing the M. bovis piv gene under control of its own promoter. The transformants and DH5a strains containing pMxL5 or pAG701 were grown in culture overnight selecting for chloramphenicol (pACYC piv-1) and/or ampicillin (pMxL5/pAG701). Plasmid DNA was then isolated and digested with KpnI, which cuts once asymmetrically within the invertible segment and once in the pBluescript vector DNA (Fig. 1); electrophoresis of restriction fragments was done as described by Marrs et al. (22). Digestion of pMxL5 with KpnI in the absence of Piv results in fragments of 9.4 and 0.5 k...

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Q pili enhance the attachment of Moraxella bovis to bovine corneas in vitro

Cited by 48 publications

References 20 publications

Type IV Pilin Proteins: Versatile Molecular Modules

Type IV Pilin Proteins: Versatile Molecular Modules

Transcriptional regulation of type 4 pilin genes and the site-specific recombinase gene, piv, in Moraxella lacunata and Moraxella bovis

Amino acid sequence homology between Piv, an essential protein in site-specific DNA inversion in Moraxella lacunata, and transposases of an unusual family of insertion elements

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