Replication and maintenance of λ plasmids devoid of the Cro repressor autoregulatory loop in Escherichia coli
Replication and maintenance of λ plasmids devoid of the Cro repressor autoregulatory loop in Escherichia coli
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DOI：
10.1006/plas.1998.1348
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发表时间：
1998-09-01
期刊：
影响因子：
2.6
通讯作者：
Wegrzyn, G
中科院分区：
文献类型：
--
作者：
Herman-Antosiewicz, A;Srutkowska, S;Wegrzyn, G
从噬菌体衍生的质粒称为质粒。这些质粒包含ori。区域和λ复制基因O和p .典型的λ质粒也含有cro基因，其产物在相对高浓度时是p(R)启动子的抑制因子。这些基因稳定地使质粒在大肠杆菌中保持在每个细胞20至50个拷贝数。根据一个普遍接受的模型，由于Cro抑制因子的自调节环（Cro基因受p(R)的控制），λ质粒的稳定维持是可能的。在这里，我们证明缺乏Cro自调节环的λ质粒也可以在大肠杆菌菌株中稳定维持。我们提供了两个这样的质粒的数据：pTC lambda 1，其中p(R)- cross区域已被p（tetA）启动子和tetR基因（编码tetR抑制因子）所取代，以及一个具有灭活cro基因的标准lambda质粒（lambda cro-null质粒）。因此，Cro抑制因子自身调节回路的存在对于维持体内的λ质粒似乎不是必需的。(C) 1998学术出版社。
Plasmids derived from bacteriophage lambda are known as lambda plasmids. These plasmids contain the ori lambda. region and lambda replication genes O and P. Typical lambda plasmids also contain the cro gene, the product of which is a repressor of the p(R) promoter when present at relatively high concentrations. These genes stably maintain the plasmid in Escherichia coli at copy numbers of 20 to 50 per cell. According to a generally accepted model, stable maintenance of lambda plasmids is possible due to the Cro repressor autoregulatory loop (the cro gene is under control of p(R)). Here we demonstrate that lambda plasmids devoid of the Cro autoregulatory loop can also be stably maintained in E. coli strains. We present data for two such plasmids: pTC lambda 1 in which the p(R)-cro region has been replaced by the p(tetA) promoter and the tetR gene (coding for the TetR repressor), and a standard lambda plasmid with inactivated cro gene (lambda cro-null plasmid). Thus, the presence of the Cro repressor autoregulatory loop does not appear to be essential to the maintenance of lambda plasmids in vivo. (C) 1998 Academic Press.