文章：

E2F与RB选择性占据RNA聚合酶III表达位点

Selective Occupation by E2F and RB of Loci Expressed by RNA Polymerase III

原文发布日期：23 January 2024

DOI: 10.3390/cancers16030481

类型: Article

开放获取: 是

英文摘要：

In all cases tested, TFIIIB is responsible for recruiting pol III to its genetic templates. In mammalian cells, RB binds TFIIIB and prevents its interactions with both promoter DNA and pol III, thereby suppressing transcription. As TFIIIB is not recruited to its target genes when bound by RB, the mechanism predicts that pol III-dependent templates will not be occupied by RB; this contrasts with the situation at most genes controlled by RB, where it can be tethered by promoter-bound sequence-specific DNA-binding factors such as E2F. Contrary to this prediction, however, ChIP-seq data reveal the presence of RB in multiple cell types and the related protein p130 at many loci that rely on pol III for their expression, including RMRP, RN7SL, and a variety of tRNA genes. The sets of genes targeted varies according to cell type and growth state. In such cases, recruitment of RB and p130 can be explained by binding of E2F1, E2F4 and/or E2F5. Genes transcribed by pol III had not previously been identified as common targets of E2F family members. The data provide evidence that E2F may allow for the selective regulation of specific non-coding RNAs by RB, in addition to its influence on overall pol III output through its interaction with TFIIIB.

摘要翻译： 

在所有测试案例中，TFIIIB负责将聚合酶III招募至其基因模板。在哺乳动物细胞中，RB蛋白结合TFIIIB并阻止其与启动子DNA及聚合酶III的相互作用，从而抑制转录。由于RB结合状态下TFIIIB无法被招募至靶基因，该机制预示聚合酶III依赖性模板不会被RB占据；这与大多数受RB调控基因的情况形成对比——在那些基因位点，RB可通过启动子结合序列特异性DNA结合因子（如E2F）被锚定。然而与这一预测相反，ChIP-seq数据显示RB在多种细胞类型中存在于多个依赖聚合酶III表达的基因位点，相关蛋白p130亦出现在包括RMRP、RN7SL及多种tRNA基因在内的位点。靶基因集合随细胞类型和生长状态而变化。在此类情况下，RB和p130的招募可通过E2F1、E2F4和/或E2F5的结合来解释。此前聚合酶III转录的基因并未被确认为E2F家族成员的常见靶标。这些数据证明，除了通过与TFIIIB相互作用影响聚合酶III整体输出外，E2F还可能介导RB对特定非编码RNA的选择性调控。

原文链接：

Selective Occupation by E2F and RB of Loci Expressed by RNA Polymerase III