The telomerase RNA pseudoknot is critical for the stable assembly of a catalytically active ribonucleoprotein
The telomerase RNA pseudoknot is critical for the stable assembly of a catalytically active ribonucleoprotein
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DOI：
10.1073/pnas.96.12.6621
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发表时间：
1999-06-08
影响因子：
11.1
通讯作者：
Blackburn, EH
中科院分区：
文献类型：
--
作者：
Gilley, D;Blackburn, EH
端粒酶是一种合成端粒DNA的核糖核蛋白逆转录酶，在所有纤毛原生动物中，端粒酶RNA组分中的假结结构在植物遗传学上是保守的。在这里，我们报告说，破坏的假结内的端粒酶RNA从嗜热四膜虫防止在体内的活性端粒酶的稳定组装，恢复假结的碱基配对潜力的补偿性变化恢复端粒酶活性基本上野生型的水平。因此，假结的拓扑结构，而不是序列是一个活跃的端粒酶的关键，此外，我们表明，假结的破坏防止协会的RNA与端粒酶的逆转录酶蛋白亚基。因此，我们提供了端粒酶RNA内端粒酶功能所需的结构基序的一个例子，并确定了端粒酶复合物形成所需的结构域。因此，我们确定了假结的生物学作用：促进催化活性核糖核蛋白的稳定组装。
Telomerase is a ribonucleoprotein reverse transcriptase that synthesizes telomeric DNA, A pseudoknot structure is phytogenetically conserved within the RNA component of telomerase in all ciliated protozoans examined. Here, we report that disruptions of the pseudoknot base pairing within the telomerase RNA from Tetrahymena thermophila prevent the stable assembly in vivo of an active telomerase, Restoring the base-pairing potential of the pseudoknot by compensatory changes restores telomerase activity to essentially wild-type levels. Therefore, the pseudoknot topology rather than sequence is critical for an active telomerase, Furthermore, we show that disruption of the pseudoknot prevents the association of the RNA with the reverse transcriptase protein subunit of telomerase. Thus, we provide an example of a structural motif within the telomerase RNA that is required for telomerase function and identify the domain that is required for telomerase complex formation, Hence, we identify a biological role for a pseudoknot: promoting the stable assembly of a catalytically active ribonucleoprotein.