Bouia A, Bringel F, Frey L, Kammerer B, Belarbi A, Guyonvarch A, Hubert J C
Laboratoire de microbiologie, Université Louis-Pasteur, Strasbourg, France.
Plasmid. 1989 Nov;22(3):185-92. doi: 10.1016/0147-619x(89)90001-2.
To construct shuttle vectors based on an endogenous replicon, we isolated a small cryptic plasmid (pLP1) from Lactobacillus plantarum CCM 1904. The nucleotide sequence (2093 bp, 38.25 GC mol%) revealed one major open reading frame encoding for a 317 amino acid protein (Rep). Comparisons with proteins encoded by other Gram-positive bacteria plasmids strongly suggest that the protein encoded by pLP1 has a replicative role. The presence of a consensus sequence including a tyrosine residue known to be the replication protein binding site to the DNA (in phage phi X174) strengthens this hypothesis. The DNA sequence contains also a sequence similar to the pC194 origin nick sequence, which initiates the plasmid replication at the plus origin, characteristic of plasmids which replicate following a rolling circle mechanism via single-stranded DNA intermediates. A set of 13 direct repeats of 17 bp could be involved in the expression of the incompatibility or in the copy number control as in the other plasmids. A promoter sequence located at the rep 5' region has been identified and is functional in Bacillus subtilis.
为构建基于内源性复制子的穿梭载体，我们从植物乳杆菌CCM 1904中分离出一个小的隐蔽质粒（pLP1）。核苷酸序列（2093 bp，38.25% GC摩尔含量）显示有一个主要的开放阅读框，编码一个317个氨基酸的蛋白质（Rep）。与其他革兰氏阳性细菌质粒编码的蛋白质进行比较强烈表明，pLP1编码的蛋白质具有复制作用。包含一个已知为DNA复制蛋白结合位点的酪氨酸残基的共有序列（在噬菌体phi X174中）的存在强化了这一假设。DNA序列还包含一个与pC194起始切口序列相似的序列，该序列在正链起始点启动质粒复制，这是通过单链DNA中间体以滚环机制复制的质粒的特征。一组13个17 bp的直接重复序列可能如其他质粒一样参与不相容性的表达或拷贝数控制。已鉴定出位于rep 5'区域的一个启动子序列，且其在枯草芽孢杆菌中具有功能。
