Characterization of the Replication, Transfer, and Plasmid/Lytic Phage Cycle of the Streptomyces Plasmid-Phage pZL12
Characterization of the Replication, Transfer, and Plasmid/Lytic Phage Cycle of the Streptomyces Plasmid-Phage pZL12
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DOI：
10.1128/jb.00123-10
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发表时间：
2010-07-01
影响因子：
3.2
通讯作者：
Qin, Zhongjun
中科院分区：
文献类型：
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作者：
Zhong, Li;Cheng, Qiuxiang;Qin, Zhongjun
我们在这里报告的分离和重组克隆的大质粒，pZL 12，从内生链霉菌sp.9R-2。pZL 12全长90，435 bp，编码112个基因，其中30个基因由一个类似噬菌体基因的大操纵子组成。在pZL 12中鉴定了复制位点（repA）和接合转移位点（traA-traC）。令人惊讶的是，含有部分纯化的噬菌体颗粒的9 R-2液体培养物的上清液感染了pZL 12的9 R-2 cured（9 R-2X）以形成噬斑，并且通过透射电子显微镜观察到噬菌体颗粒（phi ZL 12）。phi ZL 12病毒粒子的主要结构蛋白（衣壳、门和尾）由pZL 12基因编码。与噬菌体P1一样，线性phi ZL 12 DNA含有来自大部分随机pZL 12序列的末端。在线性phi ZL 12中也存在热端序列。phi ZL 12病毒粒子仅有效感染一种宿主9 R-2X，但不能感染其他18个链霉菌菌株并形成噬斑。通过感染phi ZL 12病毒体从裂解中拯救的一些9 R-2X孢子含有环状pZL 12质粒，完成了包含自主质粒pZL 12和裂解噬菌体phi ZL 12的循环。这些结果证实pZL 12是链霉菌中质粒噬菌体的第一个例子。
We report here the isolation and recombinational cloning of a large plasmid, pZL12, from endophytic Streptomyces sp. 9R-2. pZL12 comprises 90,435 bp, encoding 112 genes, 30 of which are organized in a large operon resembling bacteriophage genes. A replication locus (repA) and a conjugal transfer locus (traA-traC) were identified in pZL12. Surprisingly, the supernatant of a 9R-2 liquid culture containing partially purified phage particles infected 9R-2 cured of pZL12 (9R-2X) to form plaques, and a phage particle (phi ZL12) was observed by transmission electron microscopy. Major structural proteins (capsid, portal, and tail) of phi ZL12 virions were encoded by pZL12 genes. Like bacteriophage P1, linear phi ZL12 DNA contained ends from a largely random pZL12 sequence. There was also a hot end sequence in linear phi ZL12. phi ZL12 virions efficiently infected only one host, 9R-2X, but failed to infect and form plaques in 18 other Streptomyces strains. Some 9R-2X spores rescued from lysis by infection of phi ZL12 virions contained a circular pZL12 plasmid, completing a cycle comprising autonomous plasmid pZL12 and lytic phage phi ZL12. These results confirm pZL12 as the first example of a plasmid-phage in Streptomyces.