The mechanisms underlying multipartite genome maintenance and its functional significance in extraordinary radioresistance of Deinococcus radiodurans are not well understood. The sequences upstream to parAB operons in chrII (cisII) and MP (cisMP) could stabilize an otherwise, non-replicative colE1 plasmid, in D. radiodurans DnaA and cognate ParB proteins bound specifically with cisII and cisMP elements. The ΔcisII and ΔcisMP cells showed the reduced copy number of cognate replicons and radioresistance as compared with wild type. Fluorescent reporter-operator system inserted in chrI, chrII, and MP in wild type and cisII mutants showed the presence of all three replicons in wild-type cells. Although chrI was present in all the ΔcisII and ΔcisMP cells, nearly half of these cells had chrII and MP, respectively, and the other half had the reduced number of foci representing these replications. These results suggested that cisII and cisMP elements contain both origin of replication and parS-like functions and the secondary genome replicons (chrII and MP) are maintained independent of chrI and have roles in radioresistance of D. radiodurans.

中文翻译：

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耐辐射奇异球菌二级基因组复制子中ori和parS样功能的表征。

多部分基因组维持的机制及其在耐辐射奇异球菌的非凡抗辐射性中的功能意义尚不清楚。chrII ( cisII ) 和 MP ( cisMP ) 中parAB操纵子上游的序列可以稳定D. radiodurans DnaA 中的其他非复制型colE1质粒，并且同源 ParB 蛋白与cisII和cisMP元件特异性结合。Δ cisII和 Δ cisMP与野生型相比，细胞显示同源复制子的拷贝数和放射抗性减少。在野生型和cisII突变体中插入 chrI、chrII 和 MP 的荧光报告基因-操作系统表明野生型细胞中存在所有三个复制子。尽管 chrI 存在于所有 Δ cisII和 Δ cisMP细胞中，但这些细胞中有近一半分别具有 chrII 和 MP，而另一半细胞具有代表这些复制的病灶数量减少。这些结果表明cisII和cisMP元件同时包含复制起点和parS样函数和次级基因组复制子（chrII和MP）被保持CHRI的独立和具有在抗辐射的作用耐辐射球菌。