Cloning, mutation and distribution of a putative lipopolysaccharide biosynthesis locus in Campylobacter jejuni

Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK Author for correspondence: Julian M. Ketley. Tel: + 44 116 252 3434. Fax: +44 116 252 3378. e-mail: ket@le.ac.uk ABSTRACT Summary: A region encoding ORFs with homology to known lipopolysaccharide (LPS) biosynthesis genes was isolated from two strains of Campylobacter jejuni. One of the strains produces LPS, but the second strain is reported to produce only lipooligosaccharide (LOS) and therefore lacks the O-chain. The two strains shared six predicted ORFs, but an additional ORF, orfE, of unknown function was identified in the LOS-producing strain. Mutation of the shared wbeE ( rfbE ) homologue (orfF) or deletion of five of the seven genes reduced core reactivity with specific antiserum without affecting O-chain production. Mutation of either the capD homologue ( orfG ) or the unique orfE had no detectable effect on LOS or LPS production. The presence or absence of orfE in 36 isolates of C. jejuni did not correlate with LOS/LPS phenotype or serotype. However, after insertion of orfE into a LPS-producing orfE -negative strain the O-chain ladder was no longer detectable on Western blots. We were not able to disrupt the wbaP ( rfbP ) homologue ( orfC ) in C. jejuni . Keywords: Campylobacter , lipopolysaccharide, genetics, distribution, mutation The GenBank/EMB/DDBJ accession numbers for the C. jejuni NCTC 11168 and C. jejuni NCTC 11351 clones reported in this paper are AF001497 and AF001498 , respectively. Present address: Microscience Ltd, Dept of Infectious Diseases, Imperial College School of Medicine at The Hammersmith Campus, Du Cane Road, London W12 ONN, UK. Present address: The Wellcome Trust, 183 Euston Road, London NW1 2BE, UK.