Genome comparison in silico in Neisseria suggests integration of filamentous bacteriophages by their own transposase
Genome comparison in silico in Neisseria suggests integration of filamentous bacteriophages by their own transposase
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DOI：
10.1093/dnares/dsi021
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发表时间：
2005-12-31
期刊：
影响因子：
4.1
通讯作者：
Kobayashi, Ichizo
中科院分区：
文献类型：
--
作者：
Kawai, Mikihiko;Uchiyama, Ikuo;Kobayashi, Ichizo
在奈瑟氏菌的电子基因组比较中，我们已经鉴定出丝状前噬菌体，NF(奈瑟氏细丝噬菌体)。比较3株脑膜炎奈瑟菌和1株淋病奈瑟菌的基因组，发现了4种核因子亚型。11个完整的拷贝位于四个基因组中的不同位置。每个完整的NF拷贝两侧都有5‘-CT的复制，在其右端携带RNAseH/逆转录病毒整合酶超家族的转座酶同源物(pivNM/IRG)。这些假定的转座酶与NFS噬菌体相关蛋白的系统发育是一致的。在NFS环之后，形成一个类似启动子的序列。这些预测的环状形式(5‘-atCTatat)的交界处的序列在相应的基因座上找到了相关的质粒(PMU1)。还发现了几种结构上的变异--部分颠倒、内部删除和截断。部分倒位似乎是两个反向的5‘-CTTAT序列之间的特异性重组的产物，一个在其末端，另一个在pivNM/IRG的上游。内部缺失突变体的形成可能是通过复制转座进行的，该转座也涉及两个5‘-CTTAT序列。我们的结论是，NFS上的PivNM/IRG转座酶将它们的环状整合到含有5‘-CT的染色体序列中，并可能介导了上述重排。
We have identified filamentous prophages, Nf (Neisserial filamentous phages), during an in silico genome comparison in Neisseria. Comparison of three genomes of Neisseria meningitidis and one of Neisseria gonorrhoeae revealed four subtypes of Nf. Eleven intact copies are located at different loci in the four genomes. Each intact copy of Nf is flanked by duplication of 5'-CT and, at its right end, carries a transposase homologue (pivNM/irg) of RNaseH/Retroviral integrase superfamily. The phylogeny of these putative transposases and that of phage-related proteins on Nfs are congruent. Following circularization of Nfs, a promoter-like sequence forms. The sequence at the junction of these predicted circular forms (5'-atCTtatat) was found in a related plasmid (pMU1) at a corresponding locus. Several structural variants of Nfs-partially inverted, internally deleted and truncated-were also identified. The partial inversion seems to be a product of site-specific recombination between two 5'-CTtat sequences that are in inverse orientation, one at its end and the other upstream of pivNM/irg. Formation of internally deleted variants probably proceeded through replicative transposition that also involved two 5'-CTtat sequences. We concluded that the PivNM/Irg transposase on Nfs integrated their circular forms into the chromosomal 5'-CT-containing sequences and probably mediated the above rearrangements.