端粒长度维持与人类胚胎干细胞（hESCs）获得自我更新能力和维持基因组的稳定性密切相关。在我们的前期研究中发现，hESCs在早期培养过程中依赖于端粒酶进行端粒延长，但是其具体的调控机制不明。TERRA是近年来发现的一种端粒区域转录的非编码端粒RNA，其尾端序列与端粒酶的模版RNA组分互补，并且与转录来源的端粒区域有高亲和力，其在端粒的调控作用中备受关注。我们也发现TERRA的表达水平在进行端粒延长的早期hESCs中要明显高于端粒稳定的晚期hESCs，推测TERRA可能参与了早期hESCs端粒延长的调控。本课题拟以早期hESCs为对象，研究TERRA在hESCs端粒长度调控网络中的作用方式，并探讨这一调控网络与干细胞特性的联系。结果将揭示hESCs端粒长度调控的机制和意义，并为客观评价hESCs端粒长度的生物学意义提供研究依据。

Maintaining telomere length is closely related to human embryonic stem cells (hESCs) to obtain self-renewal capacity and maintaining genomic stability. In our previous study，telomere elongation in the early passages of cultured hESCs dependent on telomerase activity，but the specific regulatory mechanism has not been elaborated. Recent studies found that, TERRA is a kind of non-coding RNAs, which are transcribed from telomeric region. The terminal sequence of TERRA and the sequence of template RNA that is a component of telomerase are base-pair complementary, and TERRA have a high affinity with its transcriptional sources of telomeric region, so the function of TERRA is under the strong spotlight of the telomere regulation. We also found that the expression of TERRA in the early passage of telomere elongating hESCs was significantly higher than the late passage of telomere stability hESCs, presumably TERRA may participate the regulation of telomere elongation in the early passage of hESCs. This topic intends to the telomere elongated early passage of hESCs as object of study, researching the mode of action and mechanisms of TERRA in the network of telomere length regulation, and explore the relationship between the regulatory network with hESCs characteristics. The results will reveal the significance of TERRA to telomere length regulation, and provide us the theoretical reference for objective evaluation of telomere length and hESCs characteristics.