Expression of E. coli araE and mutated lacY genes in Campylobacter jejuni is not sufficient for arabinose transport.

Abstract

Aims The aim of this study was to investigate possible effects of araE and mutated lacY genes on arabinose uptake ability of C. jejuni. Methods and results This study was conducted in an attempt to develop an arabinose-inducible gene expression system for campylobacter bacteria, which are naturally refractory to transport of this sugar. The araE and lacYA177C genes known to be involved in arabinose transport in E. coli, were constitutively expressed in Campylobacter jejuni strain 11168H after integration into the chromosome via homologous recombination (1). Vectors carrying these genes also contained a reporter gene gfp under the control of arabinose-inducible promoter pBAD. These constructs were verified in E. coli by demonstrating induction of gfp in the presence of arabinose. Integration of the genes into one of the rRNA gene clusters was verified by PCR and genome sequencing. The latter also confirmed that the inserted gene clusters contained no mutations. Expression of gfp gene in the presence of arabinose inducer was monitored using fluorescence microscopy of colonies and fluorimetry using both whole cells and lysates. Low, but statistically significant difference compared to uninduced control was only detected in 11168H/lacYA177C strain. Conclusions The results of this study revealed inability of araE and lacY derivatives of C. jejuni to transport arabinose at the same level as that in E. coli indicating a remarkable difference in the biology of these bacteria Significance of study The current study will help in understanding of C. jejuni requirements for arabinose transport, and will assist in future development of inducible gene expression systems for these bacteria