The telomerase reverse transcriptase is upregulated in the majority of human cancers and contributes directly to cell transformation. Here we report that hTERT is phosphorylated at threonine 249 during mitosis by the serine/threonine kinase CDK1. Clinicopathological analyses reveal that phosphorylation of hTERT at threonine 249 occurs more frequently in aggressive cancers. Using CRISPR/Cas9 genome editing, we introduce substitution mutations at threonine 249 in the endogenous hTERT locus and find that phosphorylation of threonine 249 is necessary for hTERT-mediated RNA dependent RNA polymerase (RdRP) activity but dispensable for reverse transcriptase and terminal transferase activities. Cap Analysis of Gene Expression (CAGE) demonstrates that hTERT phosphorylation at 249 regulates the expression of specific genes that are necessary for cancer cell proliferation and tumor formation. These observations indicate that phosphorylation at threonine 249 regulates hTERT RdRP and contributes to cancer progression in a telomere independent manner.

在大多数人类癌症中，端粒酶逆转录酶被上调，并直接促进细胞转化。在这里，我们报道hTERT在丝氨酸/苏氨酸激酶CDK1的有丝分裂过程中被苏氨酸249磷酸化。临床病理分析表明，在侵袭性癌症中，苏氨酸249处hTERT的磷酸化更为频繁。使用CRISPR / Cas9基因组编辑，我们在内源性hTERT中的苏氨酸249处引入了替代突变位点，发现苏氨酸249的磷酸化是hTERT介导的RNA依赖性RNA聚合酶（RdRP）活性所必需的，但对于逆转录酶和末端转移酶的活性是必需的。基因表达的上限分析（CAGE）表明，hTERT在249位的磷酸化调节了癌细胞增殖和肿瘤形成所必需的特定基因的表达。这些观察结果表明苏氨酸249处的磷酸化调节hTERT RdRP并以端粒非依赖性方式促进癌症进展。