Cloning, sequencing and characterization of a urease gene operon from urease‐positive thermophilic Campylobacter (UPTC)

Aims:  To clone, sequence and characterize the genetic organization of urease genes within urease‐positive thermophilic Campylobacter (UPTC). Methods and Results:  An approx. 5·1‐kbp region encoding a urease gene operon was identified, when recombinant plasmid DNAs from a genomic DNA library of a Japanese isolate (CF89‐12) of UPTC were analysed. Conclusions:  Six closely spaced and putative open reading frames (ORFs) for ureA , ureB , ureE , ureF , ureG and ureH were detected. ATG codons initiated each ORF of the UPTC urease operon except for ureB and ureH , which commenced with the most probable TTG codon. Overlaps were detected between ureA and ureB and also between ureB and ureE . Probable ribosome‐binding sites and a putative ρ ‐independent transcriptional termination region were identified. Two putative promoter structures, consisting of consensus sequences at the −35 like and −10 regions were also identified. Significance and Impact of the Study:  Construction of a neighbour‐joining tree based on the nucleotide sequence data of urease genes indicated that UPTC formed a cluster with some Helicobacter organisms separate from the other urease‐producing bacteria, suggesting a commonly shared ancestry between UPTC and Helicobacter urease genes.