CHARACTERIZATION OF CAMPYLOBACTER-UPSALIENSIS FUR AND ITS LOCALIZATION IN A HIGHLY CONSERVED REGION OF THE CAMPYLOBACTER GENOME

Despite increasing recognition of the importance of Campylobacter upsa liensis in human disease little is known about either the virulence pr operties or genetics of this enteric pathogen. The complete coding seq uence of a C. upsaliensis gene has yet to be published. We have cloned and sequenced the complete iron-uptake regulatory (fur) gene from the type strain of this species. The C. upsaliensis fur homolog was isola ted from a genomic library of C. upsaliensis ATCC 43954 constructed in phage lambdaGEM-11. The open reading frame identified encodes a polyp eptide consisting of 156 amino acids. The 5'-flanking region of the C. upsaliensis fur gene contains 3 putative Fur-binding sequences and tw o catabolite activator-binding sequences indicating the potential for autogenous and cAMP-mediated regulation, respectively. Primer extensio n analysis identified a single transcription start site 262 nt upstrea m from the AUG initiation codon. Sequence analysis indicates that the Fur protein of C. upsaliensis is highly homologous (87% amino acid ide ntity) to Campylobacter jejuni Fur. Furthermore, the arrangement of th e lysS and glyA genes downstream of fur is precisely conserved in both C. upsaliensis ATCC 43954 and C. jejuni TGH9011. Using the polymerase chain reaction close linkage of fur with lysS and glyA was also obser ved among multiple isolates of C. upsaliensis, C. jejuni and C. coli s uggesting a possible functional relevance for this conserved genetic a rrangement in campylobacteria.