The genome sequence of Clostridium botulinum type C neurotoxin-converting phage and the molecular mechanisms of unstable lysogeny.
The genome sequence of Clostridium botulinum type C neurotoxin-converting phage and the molecular mechanisms of unstable lysogeny.
复制标题
DOI：
10.1073/pnas.0505503102
复制
发表时间：
2005-11
影响因子：
11.1
通讯作者：
Y. Sakaguchi;Tetsuya Hayashi;K. Kurokawa;K. Nakayama;K. Oshima;Y. Fujinaga;M. Ohnishi;E. Ohtsubo;M. Hattori;K. Oguma
中科院分区：
文献类型：
--
作者：
Y. Sakaguchi;Tetsuya Hayashi;K. Kurokawa;K. Nakayama;K. Oshima;Y. Fujinaga;M. Ohnishi;E. Ohtsubo;M. Hattori;K. Oguma
肉毒梭菌产生的肉毒神经毒素（BoNTXs）是已知毒性最强的物质之一。在七种类型的BoNTX中，C1和D型毒素（BoNTX/C1和D）的基因由噬菌体携带。外切酶C3的基因也存在于这些细胞上。在这里，我们提出了完整的基因组序列的c-st，一个代表BoNTX/C1转换酶。基因组是一个线性双链DNA，长度为185，682 bp，末端有404 bp的直接重复序列，是已知最大的温带噬菌体基因组。我们确定了198个潜在的蛋白质编码区，包括产生BoNTX/C1和外切酶C3的基因。非常例外的是，作为一种活的噬菌体，在c-st基因组上发现了许多插入序列。通过分析溶原菌c-st基因组的分子结构，我们还发现它是以环状质粒原噬菌体的形式存在的。这些特征解释了BoNTX β的不稳定溶原性，其在历史上被称为"假溶原性"。“基于c-st序列的其他BoNTX/C1和D β的PCR扫描分析进一步揭示了BoNTX β包含一个不同的噬菌体家族，可能是通过在BoNTX β及其亲属之间交换基因组片段而产生的。
Botulinum neurotoxins (BoNTXs) produced by Clostridium botulinum are among the most poisonous substances known. Of the seven types of BoNTXs, genes for type C1 and D toxins (BoNTX/C1 and D) are carried by bacteriophages. The gene for exoenzyme C3 also resides on these phages. Here, we present the complete genome sequence of c-st, a representative of BoNTX/C1-converting phages. The genome is a linear double-stranded DNA of 185,682 bp with 404-bp terminal direct repeats, the largest known temperate phage genome. We identified 198 potential protein-coding regions, including the genes for production of BoNTX/C1 and exoenzyme C3. Very exceptionally, as a viable bacteriophage, a number of insertion sequences were found on the c-st genome. By analyzing the molecular structure of the c-st genome in lysogens, we also found that it exists as a circular plasmid prophage. These features account for the unstable lysogeny of BoNTX phages, which has historically been called "pseudolysogeny." The PCR scanning analysis of other BoNTX/C1 and D phages based on the c-st sequence further revealed that BoNTX phages comprise a divergent phage family, probably generated by exchanging genomic segments among BoNTX phages and their relatives.