Setlow J K, Cabrera-Juárez E, Griffin K
J Bacteriol. 1984 Nov;160(2):662-7. doi: 10.1128/jb.160.2.662-667.1984.
The hybrid plasmid pNov1 readily acquired genetic information from the chromosome of wild-type, but not rec-2, cells. Most of the recombination had taken place 1 h after entrance of the plasmid into the cell, as judged by transformation of rec-2 by lysates made from wild-type cells exposed to pNov1. Measurement of physical transfer from radioactively labeled cellular DNA to plasmids recombining in wild-type cells failed, since there was little more radioactivity in plasmids from such cells than from labeled rec-2 recipients, in which no recombination took place. EcoRI digestion of pNov1 divided the DNA into a 1.7-kilobase-pair fragment containing the novobiocin resistance marker and a 13-kilobase-pair fragment containing all of the original vector and considerable portions homologous to the chromosome. Transformation by the large fragment alone resulted in a plasmid the size of the original pNov1. Our hypothesis to explain the data is that genetic transfer from chromosome to plasmid took place by a copy choice mechanism.
杂种质粒pNov1很容易从野生型细胞而非rec - 2细胞的染色体获取遗传信息。根据用暴露于pNov1的野生型细胞制备的裂解物对rec - 2进行转化的结果判断，大多数重组发生在质粒进入细胞1小时后。对从放射性标记的细胞DNA到在野生型细胞中重组的质粒的物理转移进行测量未成功，因为来自此类细胞的质粒中的放射性比来自未发生重组的标记rec - 2受体细胞中的放射性高不了多少。用EcoRI对pNov1进行酶切，可将DNA分为一个含新生霉素抗性标记的1.7千碱基对片段和一个含所有原始载体以及与染色体有相当大部分同源序列的13千碱基对片段。仅用大片段进行转化会产生一个与原始pNov1大小相同的质粒。我们用以解释这些数据的假说是，从染色体到质粒的基因转移是通过复制选择机制发生的。
