...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >A novel function of poly(ADP-ribosyl)ation: Silencing of RNA polymerase II-dependent transcription
【24h】

A novel function of poly(ADP-ribosyl)ation: Silencing of RNA polymerase II-dependent transcription

机译：聚（ADP-核糖基）化的新功能：沉默RNA聚合酶II依赖性转录

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Poly(ADP-ribosyl) transferase (ADPRT) is a nuclear enzyme that catalyzes the synthesis of ADP-ribose polymers from NAD(+) as well as the transfer of these polymers onto acceptor proteins. The predominant acceptor of the poly(ADP-ribose) chains appears to be the enzyme itself. The function of ADPRT is thought to be related to a number of nuclear processes. including DNA repair and transcription. In this study, it was found that polymerase II-dependent transcription in nuclear HeLa extracts was repressed in the presence of NAD(+) at concentrations as low as 1 mu M. This repression was strictly dependent on the activity of ADPRT and correlated with the auto(ADP-ribosyl)ation of the enzyme. Subsequent degradation of the ADP-ribose polymers by enzymatic activities present in the nuclear extracts restored transcriptional activity. It would appear from these results that poly(ADP-ribosyl)ation represents the key event of the mechanism underlying NAD(+)-dependent silencing of transcription. Importantly, ADPRT- and NAD(+)-dependent silencing was observed only if poly(ADP-ribosyl)ation had taken place before formation of the transcription complex was completed. That is, if the nuclear extract was preincubated for more than 15 min in the presence of template DNA, transcription was rendered entirely insensitive to NAD(+). These results suggest that poly(ADP-ribosyl)ation may prevent polymerase II-dependent transcription, but does not interfere with ongoing transcription. Taking into account the known function of ADPRT, this enzyme may facilitate recovery from DNA damage by stimulating DNA repair and silencing transcription. [References: 36]
机译：聚（ADP-核糖基）转移酶（ADPRT）是一种核酶，催化NAD（+）合成ADP-核糖聚合物以及将这些聚合物转移到受体蛋白上。聚（ADP-核糖）链的主要受体似乎是酶本身。人们认为，ADPRT的功能与许多核过程有关。包括DNA修复和转录。在这项研究中，发现在NAD（+）的存在下，低至1μM的浓度，HeLa核提取物中聚合酶II依赖性转录受到抑制。这种抑制作用严格取决于ADPRT的活性，并与ADPRT的活性相关。酶的自动（ADP-核糖基）化。随后通过核提取物中存在的酶促活性降解ADP-核糖聚合物恢复了转录活性。从这些结果看来，聚（ADP-核糖基）化代表了NAD（+）依赖性转录沉默基础机制的关键事件。重要的是，只有在转录复合物形成完成之前发生了聚（ADP-核糖基）化反应时，才能观察到ADPRT-和NAD（+）依赖性沉默。也就是说，如果在模板DNA存在下将核提取物预孵育15分钟以上，则转录对NAD（+）完全不敏感。这些结果表明，聚（ADP-核糖基）化可以阻止聚合酶II依赖性转录，但不干扰正在进行的转录。考虑到ADPRT的已知功能，该酶可通过刺激DNA修复和沉默转录促进DNA损伤的恢复。 [参考：36]

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