• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Distinct roles of transcription factors TFIIIB and TFIIIC in RNA polymerase III transcription reinitiation
【24h】

Distinct roles of transcription factors TFIIIB and TFIIIC in RNA polymerase III transcription reinitiation

机译：转录因子TFIIIB和TFIIIC在RNA聚合酶III转录重新启动中的不同作用

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

Eukaryotic RNA polymerase (Pol) III is recruited to target promoters by a stable preinitiation complex containing transcription factors TFIIIC and TFIIIB. After the first transcription cycle, reinitiation proceeds through facilitated recycling, a process by which the terminating Pol III rapidly reloads onto the same transcription unit. Here, we show that Pol III is repeatedly recaptured in vitro by the first transcribed gene, even in the presence of a juxtaposed competitor promoter complex, thus suggesting that facilitated recycling is not merely due to a stochastic reassociation process favored by the small size of class III genes. The transcription factor requirements for facilitated reinitiation were investigated by taking advantage of Pol III templates that support both TFIIIC-dependent and TFIIIC-independent transcription. A TFIIIC-less transcription system, in which TFIIIB was reconstituted from recombinant TATA box-binding protein and Brf1 proteins and a crude fraction containing the Bdp1 component, was sufficient to direct efficient Poll III recycling on short (approximate to100 bp) class III genes. Unexpectedly, however, on longer (>300 bp) transcription units, reinitiation in the presence of TFIIIB alone was compromised, and TFIIIC was further required to reestablish a high reinitiation rate. Transcription reinitiation was also severely impaired when recombinant Bdp1 protein replaced the corresponding crude fraction in reconstituted TFIIIB. The data reveal an unexpected complexity in the Pol III reinitiation mechanism and suggest the existence of a handing-back network between Pol III, TFIIIC, and TFIIIB on actively transcribed class III genes.
机译：真核RNA聚合酶（Pol）III通过包含转录因子TFIIIC和TFIIIB的稳定的预启动复合物募集到目标启动子。在第一个转录循环之后，通过便利的循环进行重新初始化，通过该过程终止的Pol III快速重新加载到同一转录单元上。在这里，我们显示，即使在存在竞争者启动子复合体的情况下，Pol III也会被第一个转录的基因在体外反复捕获，因此表明促进回收不仅是由于小分子类所支持的随机重结合过程III基因。通过利用支持TFIIIC依赖性和TFIIIC依赖性转录的Pol III模板，研究了促进重新初始化的转录因子要求。一个无TFIIIC的转录系统，其中TFIIIB由重组TATA盒结合蛋白和Brf1蛋白重组而成，并且含有Bdp1组分的粗馏分足以指导短（约100 bp）III类基因的有效Poll III回收。但是，出乎意料的是，在更长的转录单元（> 300 bp）上，仅在TFIIIB的存在下重新启动受到了损害，并且进一步需要TFIIIC重新建立高的重新启动率。当重组Bdp1蛋白取代了重组TFIIIB中的相应粗品时，转录的重新初始化也受到严重损害。数据揭示了Pol III重新启动机制中出乎意料的复杂性，并暗示了在主动转录的III类基因上Pol III，TFIIIC和TFIIIB之间存在递归网络。

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