Disease relevance of prn

• The cloned P.69 (prn) gene of B. pertussis was insertionally inactivated with a kanamycin-resistance cassette [1].
• The gene prn encoding the outer-membrane protein P.70 (pertactin) from Bordetella parapertussis has been cloned in Escherichia coli and its DNA sequence determined [2].
• The P.69 Bordetella pertussis protective antigen was expressed by use of the trc promoter from the chromosome of a Salmonella typhimurium aro vaccine strain, BRD509, by integrating the prn gene, encoding the 93-kDa precursor of this protein, into the aroC locus [3].
• Salmonella strains expressing surface-associated P.69/pertactin from a chromosomally located prn gene were significantly more invasive than isogenic parental strains [4].

High impact information on prn

• We have therefore used the RIVET system to reveal the time-course of gene expression in vivo for selected B. pertussis virulence factors (cya, fha, prn and ptx) [5].
• A strain containing a mutation in fhaB was significantly less adhesive and invasive than its parent, and a prn fhaB double mutant exhibited an even greater reduction in adhesiveness and invasiveness down to levels comparable with a Vir- strain [1].
• The analyses included serotyping of fimbriae (Fim), genotyping of the pertussis toxin S1 subunit (ptxA) and pertactin (prn), and pulsed-field gel electrophoresis (PFGE) after digestion of B. pertussis genomic DNA with XbaI restriction enzyme [6].
• In modern isolates, polymorphism was observed only in prn, ptxS1, ptxS3, and tcfA [7].
• We used a number of methods, including prn-lac fusions, reverse transcriptase PCR, and 5' rapid amplification of cDNA ends, to localize and identify the bvg-dependent 5' end of the prn transcript to the cytosine at -125 with respect to the published start site [8].

Biological context of prn

• It has been shown by transcription activation kinetics that several of the virulence factors are differentially regulated. fha is transcribed within 10 min following a bvgAS-inducing signal, while prn is transcribed after 1 h and ptx is not transcribed until 2 to 4 h after induction [9].
• We have identified cis-acting sequences necessary for expression of prn in B. pertussis by using prn-lac fusions containing alterations in the sequence upstream of the prn open reading frame [8].
• However, these data do not support the location of the prn transcription start site as previously published [8].
• Escherichia coli K-12 strain HB101 harbouring the plasmid p41869D, which encodes the full-length prn gene under the control of the tac promoter on the broad-host-range plasmid pMMB66EH, was significantly more adhesive to HEp-2 and Chinese Hamster Ovary (CHO) cells growing in culture than E. coli HB101(pMMB66EH) [4].
• Interestingly, one gene belonging to the bvg virulence regulon behaved differently: the promoter of the prn locus, coding for the outer membrane protein pertactin, involved in bacterial adhesion to eukaryotic cells, was induced after inhibition of DNA gyrase [10].

Other interactions of prn

• We determined the frequency of variants of B. pertussis pertactin (prn), and pertussis toxin subunit 1 (ptxS1) genes, restriction fragment length polymorphism (RFLP) types and fimbrial serotypes prevalent in Australia prior to, and during the 1990s [11].

Analytical, diagnostic and therapeutic context of prn

• We collected 80 Bordetella pertussis isolates in Taiwan from 1998 to 2004 and analyzed them using a combination of pulsed-field gel electrophoresis (PFGE) and sequencing of the ptxS1 and prn genes [12].
• The analysis involved serotyping, pulsed-field gel electrophoresis of chromosomal DNA after digestion with XbaI and SpeI, and sequencing of the ptxS1 and prn genes, which encode the S1 subunit of the pertussis toxin and the major adhesin pertactin, respectively [13].
• They contain ptx genes and prn alleles similar to the vaccine strain and to European isolates collected before the introduction of vaccination [14].
• This anti-P.30 serum was used in a Western blot analysis of fractionated cells of B. pertussis and E. coli harbouring the intact prn gene [15].
• From these samples we identified 28 B. pertussis, which were characterized by biochemical techniques, PCR, DNA fingerprint, prn and ptx genes sequencing, and lipopolysaccharides (LPS) pattern [16].

References