HnRNP F/H在调控端粒酶活性、组装和转运中的作用和机制研究

端粒酶是具有逆转录酶活性的RNA-蛋白质复合体，主要包括端粒酶逆转录酶hTERT和端粒酶RNA模板hTERC两个核心组分，在细胞增殖、衰老和肿瘤中发挥关键作用。在已发表的工作中我们发现核不均一核糖核蛋白F/H （hnRNP F/H）既能与hTERC 5’末端区域结合，也能与端粒酶复合体中的一些蛋白互作，并调控端粒酶的活性和端粒长度，在肿瘤细胞的增殖和干细胞的衰老中起重要作用。但hnRNP F/H调控端粒酶活性的机制并不清楚。在本项目中我们拟研究：（1）hnRNP F/H调控端粒酶活性的机制，包括对P1 helix形成、端粒酶复合体组装、hTERC成熟和端粒酶定位的影响；（2）hnRNP F/H对端粒末端结构的影响，以及是否具有染色体末端保护功能；（3）hnRNP F/H对端粒酶向端粒募集的影响。本项目对揭示hnRNP F/H在端粒酶活性、组装和转运中的作用和机制有重要意义。

Telomerase is a specialized reverse transcriptase ribonucleoprotein (RNP) complex composed of two major components, a catalytic telomerase reverse transcriptase (hTERT) protein and a noncoding RNA component (human telomerase RNA component, hTERC). Telomerase plays a critical role in unlimited cell proliferation, aging and cancer. In our published data we found that the heterogeneous nuclear ribonucleoproteins F, H1 and H2 (hnRNP F/H) bind to the 5’-end region of hTERC and also associate with telomerase holoenzyme. HnRNP F/H can modulate telomerase activity and telomere length. HnRNP F/H also play important roles in cancer cell proliferation and stem cell senescence. However, the underlying mechanism how hnRNP F/H regulate telomerase activity is largely unknown. In this project we will: (1) Investigate the mechanisms of how hnRNP F/H modulate telomerase activity, including the impact of hnRNP F/H on hTERC P1 helix formation, telomerase holoenzyme assembly, hTERC biogenesis and maturation, and telomerase translocation; (2) Exploit the impact of hnRNP F/H on the structure of telomere end, and whether hnRNP F/H have the ability to protect the chromosome end; (3) Explore the impact of hnRNP F/H on the recruitment of telomerase to telomere. The great importance of this project lies in exploring the role and mechanism of hnRNP F/H in regulating telomerase activity, assembly and trafficking.