Srivastava Preeti, Nath Niharika, Deb J K
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110 016, India.
Plasmid. 2006 Jul;56(1):24-34. doi: 10.1016/j.plasmid.2006.01.003. Epub 2006 Mar 20.
Plasmid pCR1 is a cryptic plasmid harboured by Corynebacterium renale. It is the smallest corynebacterial plasmid known to date. Although its natural host is animal corynebacteria, it can replicate in several strains of soil corynebacteria. It can also replicate in Escherichia coli, in which it is stably maintained. The copy number of pCR1 in this host is higher than that of pUC19, with which it shows unidirectional incompatibility. It is also incompatible with pBK2, a plasmid bearing the common corynebacterial replicon pBL1. Its size is 1488bp, as revealed by DNA sequencing. A total of eight open reading frames (ORF) were detected in this plasmid, the largest of which codes for a putative Rep protein of predicted molecular mass of 21kDa. The plasmid pCR1 can be mobilized by the plasmid R6K from E. coli to other corynebacteria. Sequence analysis revealed the presence of an oriT homologous to that of R64. An E. coli plasmid pKL1 shows more than 90% identity with pCR1. Like many coryenbacterial plasmids, pCR1 also replicates by rolling circle mode.
质粒pCR1是一种由肾棒状杆菌携带的隐蔽质粒。它是迄今为止已知的最小的棒状杆菌质粒。虽然它的天然宿主是动物棒状杆菌，但它能在几种土壤棒状杆菌菌株中复制。它也能在大肠杆菌中复制，并在其中稳定维持。pCR1在该宿主中的拷贝数高于pUC19，且与pUC19表现出单向不相容性。它也与携带常见棒状杆菌复制子pBL1的质粒pBK2不相容。DNA测序显示其大小为1488bp。在该质粒中总共检测到8个开放阅读框（ORF），其中最大的一个编码预测分子量为21kDa的假定Rep蛋白。质粒pCR1可被来自大肠杆菌的质粒R6K转移至其他棒状杆菌。序列分析显示存在与R64的oriT同源的序列。大肠杆菌质粒pKL1与pCR1的同一性超过90%。与许多棒状杆菌质粒一样，pCR1也通过滚环模式复制。
