...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Either bacteriophage T4 RNase H or Escherichia coli DNA polymerase I is essential for phage replication.
【24h】

Either bacteriophage T4 RNase H or Escherichia coli DNA polymerase I is essential for phage replication.

机译：噬菌体T4 RNase H或大肠杆菌DNA聚合酶I对于噬菌体复制都是必不可少的。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Bacteriophage T4 rnh encodes an RNase H that removes ribopentamer primers from nascent DNA chains during synthesis by the T4 multienzyme replication system in vitro (H. C. Hollingsworth and N. G. Nossal, J. Biol. Chem. 266:1888-1897, 1991). This paper demonstrates that either T4 RNase HI or Escherichia coli DNA polymerase I (Pol I) is essential for phage replication. Wild-type T4 phage production was not diminished by the polA12 mutation, which disrupts coordination between the polymerase and the 5'-to-3' nuclease activities of E. coli DNA Pol I, or by an interruption in the gene for E. coli RNase HI. Deleting the C-terminal amino acids 118 to 305 from T4 RNase H reduced phage production to 47% of that of wild-type T4 on a wild-type E. coli host, 10% on an isogenic host defective in RNase H, and less than 0.1% on a polA12 host. The T4 rnh(delta118-305) mutant synthesized DNA at about half the rate of wild-type T4 in the polA12 host. More than 50% of pulse-labelled mutant DNA was in short chains characteristic of Okazaki fragments. Phage production was restored in the nonpermissive host by providing the T4 rnh gene on a plasmid. Thus, T4 RNase H was sufficient to sustain the high rate of T4 DNA synthesis, but E. coli RNase HI and the 5'-to-3' exonuclease of Pol I could substitute to some extent for the T4 enzyme. However, replication was less accurate in the absence of the T4 RNase H, as judged by the increased frequency of acriflavine-resistant mutations after infection of a wild-type host with the T4 rnh (delta118-305) mutant.
机译：噬菌体T4 rnh编码一种RNA酶H，该RNA酶在体外通过T4多酶复制系统合成时从新生的DNA链中去除了核糖核酸引物（H. C. Hollingsworth and N. G. Nossal，J. Biol。Chem。266：1888-1897，1991）。本文证明，T4 RNase HI或大肠杆菌DNA聚合酶I（Pol I）对于噬菌体复制至关重要。 polA12突变不会减少野生型T4噬菌体的产生，因为polA12突变会破坏聚合酶和大肠杆菌DNA Pol I的5'至3'核酸酶活性之间的协调，也不会破坏大肠杆菌的基因。 RNase HI。从T4 RNase H中删除C端氨基酸118至305，可将噬菌体产量降低至野生型大肠杆菌宿主中野生型T4噬菌体产量的47％，RNase H有缺陷的同基因宿主中噬菌体产量的10％，并减少比polA12主机的0.1％高。 T4 rnh（delta118-305）突变体以polA12宿主中野生型T4的约一半速度合成了DNA。超过50％的脉冲标记突变DNA属于Okazaki片段的短链特征。通过在质粒上提供T4 rnh基因，可在非许可宿主中恢复噬菌体的产生。因此，T4 RNase H足以维持T4 DNA合成的高速率，但是大肠杆菌RNase HI和Pol I的5'至3'核酸外切酶可以在某种程度上替代T4酶。然而，根据T4 rnh（delta118-305）突变体感染野生型宿主后，不存在T4 RNase H的情况，复制的准确性较低。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号