Plasmid P1 replication: negative control by repeated DNA sequences.
Plasmid P1 replication: negative control by repeated DNA sequences.
复制标题
质粒 P1 复制：重复 DNA 序列的阴性对照。
DOI：
10.1073/pnas.81.20.6456
复制
发表时间：
1984
影响因子：
11.1
通讯作者：
Abeles,A
中科院分区：
文献类型：
--
作者：
Chattoraj,D;Cordes,K;Abeles,A
单位拷贝质粒P1的不相容位点incA包含在一个由9个19个碱基对重复组成的片段中。该片段的一个或多个拷贝在反式中存在时使质粒不稳定。在这里，我们发现额外的incA拷贝会干扰质粒DNA的复制，而大部分incA的删除会增加质粒的拷贝数。因此，印加对复制不是必需的，但对复制的控制是必需的。当克隆到高拷贝数的载体中时，每个只包含三个重复的incA片段片段可以有效地破坏P1质粒的稳定性。这一结果使得incA不太可能指定一个监管产品。我们的体内结果表明，重复DNA序列本身通过滴定p1决定的蛋白质RepA来负性地控制复制，这是复制所必需的。与这一假设相一致的是，在体外观察到RepA蛋白与incA片段结合。
The incompatibility locus, incA, of the unit-copy plasmid P1 is contained within a fragment that is essentially a set of nine 19-base-pair repeats. One or more copies of the fragment destabilizes the plasmid when present in trans. Here we show that extra copies of incA interfere with plasmid DNA replication and that a deletion of most of incA increases plasmid copy number. Thus, incA is not essential for replication but is required for its control. When cloned in a high-copy-number vector, pieces of the incA fragment that each contain only three repeats destabilize P1 plasmids efficiently. This result makes it unlikely that incA specifies a regulatory product. Our in vivo results suggest that the repeating DNA sequence itself negatively controls replication by titrating a P1-determined protein, RepA, that is essential for replication. Consistent with this hypothesis is the observation that the RepA protein binds to the incA fragment in vitro.