Preferential replication-dependent mutagenesis in the lagging DNA strand inEscherichia coli
Preferential replication-dependent mutagenesis in the lagging DNA strand inEscherichia coli
复制标题
大肠杆菌滞后 DNA 链中的选择性复制依赖性诱变
DOI：
10.1007/bf02174114
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
H. Doi
中科院分区：
文献类型：
--
作者：
T. Iwaki;K. Kohno;Y. Kano;N. Goshima;F. Imamoto;A. Kawamura;Y. Ishino;M. Yara;M. Furusawa;H. Doi
在对氯霉素（Cm）和四环素（Tc）的抗性编码结构基因中，由−1移码或一个碱基取代引起的突变频率在几个DNA复制循环中进行了跟踪，发现其差异有几倍，这取决于质粒上基因相对于（单向ColE 1型）复制方向的方向。当报告基因以与起始方向相同的方向存在于质粒中时，突变频率较高，即，当转录模板是滞后子链时，比当基因以相反方向插入时。这种具有不同极性的基因的回复频率的显著差异仅在dnaQ 49突变体诱导后的细胞生长的短暂时期（几个复制循环）中得到证明，但在允许增加复制循环次数时没有观察到，最可能是由于突变固定到两条链中。在Cm基因中具有错配碱基对的突变的中间体DNA被证明被复制成两个子代DNA分子;一个是从具有突变的模板链合成的氯霉素抗性（CmR）DNA，另一个是从没有突变的模板链合成的Cms DNA。我们的研究结果表明，复制依赖的诱变可能会优先发生在滞后链。
The mutation frequencies attributable to −1 frameshift or one-base substitution in the structural genes coding for resistance to chloramphenicol (Cm) and tetracycline (Tc) were followed over several cycles of DNA replication, and found to differ several-fold, depending on the orientation of the gene on the plasmid with respect to the direction of (unidirectional ColE1-type) replication. The mutation frequency was higher when the reporter gene was present in the plasmid in the same orientation as the direction of the origin, i.e., when the transcription template is the lagging daughter strand, than when the gene was inserted in the opposite orientation. This significant difference in reversion frequencies of genes with different polarities was demonstrated only for a brief period of cell growth (several cycles of replication) after induction of thednaQ49 mutator, but was not observed when an increased number of replication cycles, was permitted, most probably due to fixation of the mutation into both strands. The mutated intermediate DNA which possesses a misaligned basepair in the Cm gene was demonstrated to be replicated into two progeny DNA molecules; one is the chloramphenicol-resistant (CmR) DNA synthesized from the template strand having the mutation and the other is the Cms DNA from the template strand without mutation. Our results suggest that replication-dependent mutagenesis may occur preferentially in the lagging strand.
DOI：
10.1073/pnas.78.7.4180
发表时间：
1981-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
CHRISTIE, GE;FARNHAM, PJ;PLATT, T
通讯作者：
PLATT, T