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

细菌逆转录酶负责合成卫星RNA-DNA复合体，称为多拷贝单链DNA （msDNA）。合成msDNA所需的遗传元件称为return，它由msDNA编码区msr-msd区和逆转录酶编码区ret基因组成。虽然返回和msDNA的作用尚不清楚，但据报道，在细胞中msDNA过量产生的条件下，埃希氏菌线圈的突变频率增加。到目前为止，我们已经在一些弧菌物种中证明了msDNA的存在，如霍乱弧菌、副溶血性弧菌等，并克隆了它们染色体的返回区，在其他致病性细菌中也发现了msDNA，如肠致病性大肠杆菌、沙门氏菌等。最近有人提出msDNA和/或逆转录酶与细菌致病性之间的关系。在霍乱弧菌中，只有O1和O139血清群是流行性霍乱的病原体，所有其他非O1 /非O139菌株基本上与流行性霍乱无关。在这项研究中，为了探讨msDNA和/或逆转录酶与霍乱弧菌致病性的关系，我们检测了不同霍乱弧菌血清群中msDNA的存在和返回。因此，我们发现所有的O1和O139菌株在长度上产生相同的msDNA。然而，非o1 /非o139菌株不含msDNA，这意味着霍乱弧菌的致病性与msDNA和/或逆转录酶之间存在强烈的关系。此外，在O1和O139菌株的同一整合位点插入相同的返回物。另一方面，在非o1 /非139菌株中，多个不同长度的片段取代了返回。

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.