Abstract:

Objective To study the features of gene composition and distribution of three common plasmids among different Yersinia pestis strains. Methods The global structure of three plasmids, pMT1, pCD1, and pPCP1, in the nine Y. pestis strains with completed whole genome sequencing was comparatively analyzed by homologous alignment of coding sequences and automatic analysis using the Mauve software. Results The pMT1 of Y. pestis showed rearrangement of large gene fragments, and it was divided into four major gene blocks. The plasmid structures of pMT1 in Orientalis Biovar strain CO92, Medievalis Biovar strain KIM, and Microtus Biovar strain 91001 were different from each other. The plasmid structures of pMT1 in all the other six Antiqua Biovar strains were almost identical, yet different from those of CO92, KIM, and 91001. Plasmid pCD1 was divided into three major gene blocks;however, the global structure of the plasmid was the same among all strains except a different insertion position of IS100. The order and orientation of all coding sequences in plasmid pPCP1 were consistent in all strains. Conclusion Plasmids pCD1 and pPCP1 have conservative gene structure among different Y. pestis strains. A certain degree of variation in the plasmid structure of pMT1 has occurred during the long-term evolution of Y. pestis.

Key words: Y. pestis, Plasmid, Structure

摘要：

目的 研究鼠疫菌基因组中3种常见质粒的基因构成和分布特征。方法 应用编码基因序列相似性比对和生物信息学软件自动分析2种方法,分别对国际上已完成全基因组测序的9株鼠疫菌的鼠毒素质粒(pMT1)、低钙反应质粒(pCD1)和鼠疫菌素质粒(pPCP1)进行整体结构的比较分析。结果 pMT1质粒上存在基因大片段的重新排列,整条质粒被划分成4个主要的基因模块。CO92、KIM和91001菌株分属于东方型、中世纪型和田鼠型3个不同的生物型,他们的pMT1质粒结构各有特点;Nepal 516等其余6株菌均是古典型鼠疫菌,他们的pMT1质粒结构基本一致,且与其他3个生物型鼠疫菌株的pMT1质粒结构不同。pCD1质粒被划分成3个主要的基因模块,但整体结构在不同菌株中并无差异,只有IS100在质粒中的插入位置各不相同。pPCP1质粒上所有编码基因的排列顺序和方向在各菌株中完全相同。结论 鼠疫菌pCD1和pPCP1质粒的基因结构比较稳定,而pMT1质粒结构在鼠疫菌的长期进化过程中发生了一定程度的变异。

关键词: 鼠疫耶尔森菌, 质粒, 结构