Abstract

Antirepressor proteins of bacteriophages are chiefly involved in interfering with the function of the repressor protein and forcing the bacteriophage to adopt the lytic cycle. The genome of Staphylococcus aureus phage, Phi11 has already been sequenced; from the genome sequence, we amplified gp07 gene and analysed its involvement in the developmental pathway of Phi11. Our results indicate that Gp07 functions as a novel antirepressor and regulates the developmental pathway of Phi11 by enhancing the binding of the Cro repressor protein to its cognate operator. We also report our finding that the CI repressor protein of Phi11 binds to the putative operator of Gp07 and regulates its expression. We further report that S.aureus transcriptional repressor LexA and coprotease RecA play a crucial role in the lytic–lysogenic switching in Phi11. We also identified that the N-terminal domain (Bro-N) of Gp07 is actually responsible for enhancing the binding of Cro repressor to its cognate operator. Our results suggest that Phi11 prophage induction is different from other bacteriophages. This study furnishes a first-hand report regarding the regulation involved in the developmental pathway of Phi11.

中文翻译：

---

金黄色葡萄球菌温带噬菌体Phi11的溶菌原转换相关基因调控研究。

摘要

噬菌体的抗阻遏蛋白主要参与干扰阻遏蛋白的功能，并迫使噬菌体采取裂解循环。金黄色葡萄球菌噬菌体Phi11的基因组已经测序。从基因组序列中，我们扩增了gp07基因，并分析了其在Phi11发育途径中的参与。我们的结果表明，Gp07发挥了新型的抗阻遏物的作用，并通过增强Cro阻遏物蛋白与其同源操纵子的结合来调节Phi11的发育途径。我们还报告了我们的发现，即Phi11的CI阻遏蛋白与公认的Gp07操纵子结合并调节其表达。我们进一步报告金黄色葡萄球菌转录阻遏物LexA和共蛋白酶RecA在Phi11的溶菌原性转换中起关键作用。我们还确定，Gp07的N末端域（Bro-N）实际上负责增强Cro阻遏物与其同源操纵子的结合。我们的结果表明，Phi11噬菌体诱导不同于其他噬菌体。这项研究提供了有关Phi11发育途径中调控的第一手报告。