Purification and characterization of a transcription factor that confers promoter specificity to human RNA polymerase I.
Purification and characterization of a transcription factor that confers promoter specificity to human RNA polymerase I.
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赋予人 RNA 聚合酶 I 启动子特异性的转录因子的纯化和表征。
DOI：
10.1128/mcb.5.6.1358-1369.1985
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发表时间：
1985
影响因子：
5.3
通讯作者：
Tjian,R
中科院分区：
文献类型：
--
作者：
Learned,RM;Cordes,S;Tjian,R
将全细胞HeLa提取物分级分离成准确体外转录人rRNA所需的两种组分。一个组分含有内源性RNA聚合酶I，第二个组分含有赋予RNA聚合酶I启动子选择性的因子（SL 1）。突变体模板的分析表明，rRNA启动子的核心控制元件是由SL1激活转录所必需的。我们通过柱色谱法将SL 1纯化了大约100，000倍，并且已经表明添加SL 1可以重新编程原本不允许的小鼠转录系统，以识别并启动来自人rDNA的准确RNA合成。针对SL 1产生的抗体优先结合位于灵长类细胞核仁中的蛋白质，并特异性抑制从人rRNA启动子起始的体外转录。相比之下，抗SL 1不与啮齿动物细胞的核仁反应，并且通过源自小鼠细胞的转录系统对小鼠rRNA的体外合成没有影响。这些研究结果表明，SL1是一个选择性因子存在于核仁中，赋予启动子识别RNA聚合酶I，并可以区分来自不同物种的rRNA启动子。
A whole-cell HeLa extract was fractionated into two components required for accurate in vitro transcription of human rRNA. One fraction contained endogenous RNA polymerase I, and the second component contained a factor (SL1) that confers promoter selectivity to RNA polymerase I. Analysis of mutant templates suggests that the core control element of the rRNA promoter is required for activation of transcription by SL1. We purified SL1 approximately 100,000-fold by column chromatography and have shown that the addition of SL1 can reprogram the otherwise nonpermissive mouse transcription system to recognize and initiate accurate RNA synthesis from human rDNA. Antibodies raised against SL1 bind preferentially to a protein localized in the nucleolus of primate cells and specifically inhibit in vitro transcription initiating from the human rRNA promoter. By contrast, anti-SL1 does not react with the nucleolus of rodent cells and has no effect on the in vitro synthesis of mouse rRNA by a transcription system derived from mouse cells. These findings suggest that SL1 is a selectivity factor present in the nucleolus that imparts promoter recognition to RNA polymerase I and that can discriminate between rRNA promoters from different species.