科研之友
微信
新浪微博
Facebook
分享链接
摘要
Erythritol utilization is a characteristic of pathogenic Brucella abortus strains. The attenuated vaccine strain gig is the only Brucella strain that is inhibited by erythritol, so a role for erythritol metabolism in virulence is suspected. A chromosomal fragment from the pathogenic strain B. abortus 2308 containing genes for the utilization of erythritol was cloned taking advantage of an erythritol-sensitive Tn5 insertion mutant. The nucleotide sequence of the complete 7714 bp fragment was determined. Four ORFs were identified in the sequence. The four genes were closely spaced, suggesting that they were organized as a single operon (the ery operon), The first gene (eryA) encoded a 519 aa putative erythritol kinase, The second gene (eryB) encoded an erythritol phosphate dehydrogenase, The function of the third gene (eryC) product was tentatively assigned as D-erythrulose-1-phosphate dehydrogenase and the fourth gene (eryD) encoded a regulator of ery operon expression. The operon promoter was located 5' to eryA, and contained an IHF (integration host factor) binding site. Transcription from this promoter was repressed by EryD, and stimulated by erythritol. Functional IHF was required for expression of the operon in Escherichia coli, suggesting a role for IHF in its regulation in a. abortus. The results obtained will be helpful in clarifying the role of erythritol metabolism in the virulence of Brucella spp.
- 出版日期2000-2
