Sozhamannan S, Dabert P, Moretto V, Ehrlich S D, Gruss A
Institut de Biotechnologie, Institut National de la Recherche Agronomique--Domaine de Vilvert, Jouy en Josas, France.
J Bacteriol. 1990 Aug;172(8):4543-8. doi: 10.1128/jb.172.8.4543-4548.1990.
Staphylococcus aureus plasmid pE194 manifests a natural thermosensitivity for replication and can be established in several species, both gram positive and gram negative, thus making it attractive for use as a delivery vector. Like most characterized plasmids of gram-positive bacteria, pE194 generates single-stranded DNA. The direction of pE194 replication is clockwise, as determined by the strandedness of free single-stranded DNA. Significant homology exists between a 50-base-pair sequence in the origin of pE194 and sequences present in plasmids pMV158 (Streptococcus agalactiae), pADB201 (Mycoplasma mycoides), and pSH71 (Lactococcus lactis). We used an initiation-termination reaction, in which pE194 initiates replication at its own origin and is induced to terminate at the related pMV158 sequence, to demonstrate that pE194 replicates by a rolling-circle mechanism; the initiation nick site was localized to an 8-base-pair sequence.
金黄色葡萄球菌质粒pE194对复制表现出天然的温度敏感性，并且可以在革兰氏阳性和革兰氏阴性的多个物种中建立，因此使其成为用作递送载体的有吸引力的选择。与大多数已表征的革兰氏阳性细菌质粒一样，pE194产生单链DNA。如由游离单链DNA的链性所确定的，pE194复制的方向是顺时针的。pE194的复制起点中的一个50碱基对序列与质粒pMV158（无乳链球菌）、pADB201（丝状支原体）和pSH71（乳酸乳球菌）中存在的序列之间存在显著的同源性。我们使用了一种起始-终止反应，其中pE194在其自身的起点启动复制，并被诱导在相关的pMV158序列处终止，以证明pE194通过滚环机制进行复制；起始切口位点定位在一个8碱基对序列上。
