Analysis of a genomic island housing genes for DNA S-modification system in Streptomyces lividans 66 and its counterparts in other distantly related bacteria
Analysis of a genomic island housing genes for DNA S-modification system in Streptomyces lividans 66 and its counterparts in other distantly related bacteria
复制标题
对浅青紫链霉菌 66 及其在其他远缘细菌中的对应物中 DNA S 修饰系统的基因组岛的分析。
DOI：
10.1111/j.1365-2958.2007.05846.x
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发表时间：
2007-08-01
影响因子：
3.6
通讯作者：
Deng, Zixin
中科院分区：
文献类型：
--
作者：
He, Xinyi;Ou, Hong-Yu;Deng, Zixin
测定了变铅青链霉菌66基因组岛（GI）SLG的全序列（92 770 bp），该基因组岛编码一种新的DNA S-修饰系统（dnd）。其总G+C含量为67.8%，低于已测序的三个链霉菌基因组。在85个预测的SLG开放阅读框（ORF）中，有22个ORF与已知蛋白质同源性较低。SLG显示由四个模块组成的镶嵌结构，表明其形成过程中的多次重组事件。观察到SLG的自发切除和环化，并且切除率似乎由MNNG暴露诱导至少五倍。使用构建的SLG迷你岛，我们证明了Slg 01，P4样整合酶，足以促进SLG整合，切除和环化。11个对应的dnd集群，这也映射到地理标志在10条染色体和质粒，被发现在分类无关的细菌物种从不同的地理生态位。此外，c.在对74株放线菌的调查中，发现10%的放线菌具有dnd簇。12种细菌中dnd簇的比较强烈表明，这些带有dnd的元件可能是从类似于盐浮游假交替单胞菌TAC 125的质粒起源染色体II的共同祖先进化而来的。
The complete sequence (92 770 bp) of a genomic island (GI) named SLG from Streptomyces lividans 66, encoding a novel DNA S-modification system (dnd), was determined. Its overall G+C content was 67.8%, lower than those of three sequenced Streptomyces genomes. Among 85 predicted open reading frames (ORFs) in SLG, 22 ORFs showed little homology with previously known proteins. SLG displays a mosaic structure composed of four modules, indicative of multiple recombination events in its formation. Spontaneous excision and circularization of SLG was observed, and the excision rate appeared to be induced at least fivefold by MNNG exposure. Using constructed mini-islands of SLG, we demonstrated that Slg01, a P4-like integrase, was sufficient to promote SLG integration, excision and circularization. Eleven counterpart dnd clusters, which also mapped to GIs in 10 chromosomes and a plasmid, were found in taxonomically unrelated bacterial species from various geographic niches. Additionally, c. 10% of actinomycetes were found to possess a dnd cluster in a survey involving 74 strains. Comparison of dnd clusters in the 12 bacteria strongly suggests that these dnd-bearing elements might have evolved from a common ancestor similar to plasmid-originated chromosome II of Pseudoalteromonas haloplanktis TAC125.