Characterization of transcription from TATA-less promoters: identification of a new core promoter element XCPE2 and analysis of factor requirements.
Characterization of transcription from TATA-less promoters: identification of a new core promoter element XCPE2 and analysis of factor requirements.
复制标题
DOI：
10.1371/journal.pone.0005103
复制
发表时间：
2009
期刊：
影响因子：
3.7
通讯作者：
Takada S
中科院分区：
文献类型：
--
作者：
Anish R;Hossain MB;Jacobson RH;Takada S
超过 80% 的哺乳动物蛋白质编码基因由无 TATA 的启动子驱动，这些启动子通常显示多个转录起始位点 (TSS)。然而，人们对这类启动子的核心启动子 DNA 序列或转录起始机制知之甚少。在这里，我们鉴定了一个新的核心启动子元件XCPE2（X核心启动子元件2）（共有序列：A/C/G-C-C/T-C-G/A-T-T-G/A-C-C/A+1-C/T），它可以指导乙型肝炎病毒X基因mRNA第二个TSS的特异性转录。 XCPE2 序列也可以在人类启动子区域中找到，并且通常似乎驱动多个含有 TSS 的无 TATA 启动子内的起始位点之一。为了深入了解此类启动子的转录起始机制，我们使用免疫耗竭的核提取物和纯化的因子通过体外转录实验检查了几种通用转录因子的要求。我们的结果表明，XCPE2 驱动的转录至少使用 TFIIB、TFIID 或游离 TBP、RNA 聚合酶 II (RNA pol II) 和包含 MED26 的介体复合物，但不使用 Gcn5。因此，XCPE2驱动的转录可以通过不同于先前描述的包含起始子（Inr）或下游启动子元件（DPE）的启动子的TAF依赖性机制、包含酵母TATA的启动子的TBP-和SAGA（Spt-Ada-Gcn5-乙酰转移酶）依赖性机制或TFTC的机制来进行。 某些含 Inr 且不含 TATA 的启动子的（不含 TBP-含 TAF 复合物）依赖机制。使用 XCPE2 启动子和纯化因子的 EMSA 测定进一步表明，XCPE2 启动子识别需要一组不同于 TATA 盒、Inr 或 DPE 启动子识别的因子。我们鉴定了一个新的核心启动子元件 XCPE2，它存在于多个含有 TSS 的无 TATA 启动子中。 XCPE2 驱动的启动子的启动子识别和转录起始机制似乎与先前显示的显示单个“集中”TSS 的经典启动子的机制不同。我们的研究深入了解了从多个含有 TSS 的无 TATA 启动子进行 RNA Pol II 转录的新机制。
More than 80% of mammalian protein-coding genes are driven by TATA-less promoters which often show multiple transcriptional start sites (TSSs). However, little is known about the core promoter DNA sequences or mechanisms of transcriptional initiation for this class of promoters. Here we identify a new core promoter element XCPE2 (X core promoter element 2) (consensus sequence: A/C/G-C-C/T-C-G/A-T-T-G/A-C-C/A+1-C/T) that can direct specific transcription from the second TSS of hepatitis B virus X gene mRNA. XCPE2 sequences can also be found in human promoter regions and typically appear to drive one of the start sites within multiple TSS-containing TATA-less promoters. To gain insight into mechanisms of transcriptional initiation from this class of promoters, we examined requirements of several general transcription factors by in vitro transcription experiments using immunodepleted nuclear extracts and purified factors. Our results show that XCPE2-driven transcription uses at least TFIIB, either TFIID or free TBP, RNA polymerase II (RNA pol II) and the MED26-containing mediator complex but not Gcn5. Therefore, XCPE2-driven transcription can be carried out by a mechanism which differs from previously described TAF-dependent mechanisms for initiator (Inr)- or downstream promoter element (DPE)-containing promoters, the TBP- and SAGA (Spt-Ada-Gcn5-acetyltransferase)-dependent mechanism for yeast TATA-containing promoters, or the TFTC (TBP-free-TAF-containing complex)-dependent mechanism for certain Inr-containing TATA-less promoters. EMSA assays using XCPE2 promoter and purified factors further suggest that XCPE2 promoter recognition requires a set of factors different from those for TATA box, Inr, or DPE promoter recognition. We identified a new core promoter element XCPE2 that are found in multiple TSS-containing TATA-less promoters. Mechanisms of promoter recognition and transcriptional initiation for XCPE2-driven promoters appear different from previously shown mechanisms for classical promoters that show single “focused” TSSs. Our studies provide insight into novel mechanisms of RNA Pol II transcription from multiple TSS-containing TATA-less promoters.
登录
查看更多内容
影响因子：
10.5
作者：
Butler, JEF;Kadonaga, JT
通讯作者：
Kadonaga, JT
影响因子：
10.5
作者：
Lim, CY;Santoso, B;Kadonaga, JT
通讯作者：
Kadonaga, JT
影响因子：
64.5
作者：
Basehoar, AD;Zanton, SJ;Pugh, BF
通讯作者：
Pugh, BF
影响因子：
12.3
作者：
Ohler U;Liao GC;Niemann H;Rubin GM
通讯作者：
Rubin GM
影响因子：
5.3
作者：
Hilton, TL;Li, Y;Wang, EH
通讯作者：
Wang, EH