Varella Coelho Marcus Livio, Ceotto Hilana, Madureira Danielle Jannuzzi, Nes Ingolf F, Bastos Maria do Carmo de Freire
Departamento de Genética, Instituto de Biologia, Mexico City, Mexico.
J Microbiol. 2009 Jun;47(3):327-36. doi: 10.1007/s12275-009-0044-7. Epub 2009 Jun 26.
Plasmid pRJ6 is the first known bacteriocinogenic mobilizable (Mob) plasmid of Staphylococcus aureus. Its Mob region is composed of four mob genes (mobCDAB) arranged as an operon, a genetic organization uncommon among S. aureus Mob plasmids. oriT (pRJ6) was detected in a region of 431 bp, positioned immediately upstream of mobC. This region, when cloned into pCN37, was able to confer mobilization to the re-combinant plasmid only in the presence of pRJ6. The entire Mob region, including oriT (pRJ6), is much more similar to Mob regions from several coagulase-negative staphylococci plasmids, although some remarkable similarities with S. aureus Mob plasmids can also be noted. These similarities include the presence within oriT (pRJ6) of the three mcb (MobC binding sites), firstly described in pC221 and pC223, an identical nick site also found in these same plasmids, and a nearly identical sra(pC223) site (sequence recognized by MobA). pRJ6 was successfully transferred to S. epidermidis by conjugation in the presence of the conjugative plasmid pGOl. Altogether these findings suggest that pRJ6 might have been originally a coagulase-negative staphylococci plasmid that had been transferred successfully to S. aureus.
质粒pRJ6是已知的首个金黄色葡萄球菌产细菌素可移动（Mob）质粒。其Mob区域由四个作为操纵子排列的mob基因（mobCDAB）组成，这种基因组织在金黄色葡萄球菌Mob质粒中并不常见。oriT（pRJ6）在一个431 bp的区域中被检测到，位于mobC的紧邻上游。当该区域被克隆到pCN37中时，仅在存在pRJ6的情况下才能赋予重组质粒可移动性。整个Mob区域，包括oriT（pRJ6），与几种凝固酶阴性葡萄球菌质粒的Mob区域更为相似，尽管也可以注意到与金黄色葡萄球菌Mob质粒有一些显著的相似之处。这些相似之处包括oriT（pRJ6）内存在三个mcb（MobC结合位点），这首先在pC221和pC223中被描述，在这些相同质粒中也发现了相同的切口位点，以及一个几乎相同的sra（pC223）位点（被MobA识别的序列）。在接合性质粒pGO1存在的情况下，通过接合作用，pRJ6成功转移到表皮葡萄球菌中。总之，这些发现表明pRJ6可能最初是一个凝固酶阴性葡萄球菌质粒，已成功转移到金黄色葡萄球菌中。
