Roles of reverse transcriptase and its cDNA product as new virulence factors in Vibrio infectious disease

点击翻译按钮获取中文摘要

Bacterial reverse transcriptase is responsible for the synthesis of satellite RNA-DNA complex called multicopy single-stranded DNA (msDNA).A genetic element required for the msDNA synthesis is named return which consists of the msr-msd region, a coding region for the msDNA and the ret gene, a coding region for reverse transcriptase. Although the role(s) of return and msDNA remains unclear, it has been reported that mutation frequency was increased in Escherichia coil under conditions in which msDNA was overproduced in a cell.To date, we have demonstrated the existence of msDNA in some Vibrio species, such as V. choleras, V. parahaemolyticus, and so on, and cloned the return regions from their chromosomes, msDNAs have also been found in other pathogenic bacteria, such as enteropathogenic E. coil, Salmonella, and so on. A relationship between msDNA and / or reverse transcriptase and bacterial pathogenicity has been suggested recently.In V. choleras, only O1 and O139 serogroups are the causative agents of epidemic cholera and all the other non-O1 / non-O139 strains are not basically associated with epidemic cholera. In this study, to investigate the relationship between msDNA and / or reverse transcriptase and pathogenictiy in V. choleras, we examined the existence of msDNA and return in different serogroups of V. cholera. Thus we found that all O1 and O139 strains we have tested produced the same msDNA in length. However, non-O1 / non-O139 strains do not contain msDNA, meaning that a relationship between pathogenicity of V.cholerae and msDNA and / or reverse transcriptase was strongly indicated. In addition, the same return is inserted into the same integration site of the O1 and O139 strains. On the other hand, several fragments of different length replace the return in the non-O1 / non-139 strains.