Cloning, sequencing and expression of full-length Campylobacter invasion antigen B gene operon from Campylobacter lari

A novel PCR primer pair for amplification of full‐length cia B gene from thermophilic campylobacters, generated an amplicon of approximately 2.2 kilo base pairs (kbp) with all 18 isolates (n = 7 for urease‐negative (UN) C. lari; n = 9 urease‐positive thermophilic Campylobacter (UPTC); n = 1 C. jejuni; n = 1 C. coli). The putative open reading frame (ORF) of the cia B from C. lari isolates consisted of 1,833 bp similarly, but differing from those of C. jejuni and C. coli isolates. The putative promoter structures consisting of a semi‐conserved T ‐rich sequence and a consensus sequence at the –10 region were identified upstream of the putative ORF in all the C. lari isolates. A start codon ATG and a probable ribosome binding site were also identified in all the isolates. In addition, two distinctly different and taxon (UN C. lari and UPTC) dependent hypothetically intrinsic ρ ‐independent transcriptional terminators for the cia B were identified to occur within the C. lari. Reverse transcription–PCR analysis identified the transcription of cia B gene in the C. lari cells. The neighbor joining tree suggested that the nucleotide sequence information of the cia B had molecular discrimination efficacy among UN C. lari, UPTC, C. jejuni and C. coli organisms. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)