Functional multimerization of the human telomerase reverse transcriptase
Functional multimerization of the human telomerase reverse transcriptase
复制标题
DOI：
10.1128/mcb.21.18.6151-6160.2001
复制
发表时间：
2001-09-01
影响因子：
5.3
通讯作者：
Harrington, L
中科院分区：
文献类型：
--
作者：
Beattie, TL;Zhou, W;Harrington, L
端粒酶在哺乳动物中以一个大的复合物（类似于1,000 kDa）存在，至少由端粒酶RNA和催化亚基端粒酶逆转录酶（TERT）组成。在酿酒酵母中，端粒酶似乎在体内起相互依赖的二聚体或多聚体的作用（J. Prescott和E. H. Blackburn，Genes Dev. 11：2790-2800，1997）。然而，多聚化的要求尚不清楚，并且仍然不清楚端粒酶是否以多聚体形式存在于其他生物体中。我们在这里表明，人端粒酶（hTERT）形成一个功能性的多聚体在兔网织红细胞裂解物重建试验和人细胞提取物。两个单独的无催化活性的TERT蛋白可以反式互补以重建催化活性。这种互补需要一个hTERT的氨基末端和第二个hTERT的逆转录酶和C-末端结构域。端粒酶RNA必须仅与后一个hTERT结合，以使端粒酶活性发生重建。端粒酶的多聚化也促进了体外和体内底物的识别和延伸。这些数据表明，催化核心的人端粒酶可能存在作为一个功能合作的二聚体或多聚体在体内。
The telomerase enzyme exists as a large complex (similar to1,000 kDa) in mammals and at minimum is composed of the telomerase RNA and the catalytic subunit telomerase reverse transcriptase (TERT). In Saccharomyces cerevisiae, telomerase appears to function as an interdependent dimer or multimer in vivo (J. Prescott and E. H. Blackburn, Genes Dev. 11:2790-2800, 1997). However, the requirements for multimerization are not known, and it remained unclear whether telomerase exists as a multimer in other organisms. We show here that human TERT (hTERT) forms a functional multimer in a rabbit reticulocyte lysate reconstitution assay and in human cell extracts. Two separate, catalytically inactive TERT proteins can complement each other in trans to reconstitute catalytic activity. This complementation requires the amino terminus of one hTERT and the reverse transcriptase and C-terminal domains of the second hTERT. The telomerase RNA must associate with only the latter hTERT for reconstitution of telomerase activity to occur. Multimerization of telomerase also facilitates the recognition and elongation of substrates in vitro and in vivo. These data suggest that the catalytic core of human telomerase may exist as a functionally cooperative dimer or multimer in vivo.