Liang Cuicui, Wang Yuhao, Wang Yujie, Chen Xuemei, Guo Huarong
1 Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
2 Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Zoolog Sci. 2017 Oct;34(5):419-428. doi: 10.2108/zs160130.
Telomerase reverse transcriptase (TERT), a catalytic subunit of telomerase, plays a key role in the activity and biological functions of telomerase. In the present study we isolated and characterized the full-length cDNA and DNA sequences of the TERT gene (MeTERT) from Metapenaeus ensis. MeTERT cDNA was 4239 bp in length, which consisted of a 369 bp 5'UTR, a 3231 bp open reading frame encoding 1076 amino acids, and a 639 bp 3'UTR. The genomic DNA of MeTERT had only two introns, similar to beetle (two introns) and silkworm (intronless). The MeTERT protein showed only 5.2-7.9% identity with other known TERTs but contained all the four primary TERT domains of the N-terminal TEN, RNA binding domain (TRBD), reverse transcriptase (RT) and C-terminus CTE. Expression pattern analysis by RT-qPCR showed that, the MeTERT mRNA transcripts could be detected in all the tested samples, with relatively higher expression level in the gill, mysis, Oka organ and egg, but lower level in muscle, ovary, in vitro cultured 3-d Oka organ cells and heart. The significant decrease of MeTERT expression in the in vitro cultured 3-d Oka organ primary cells compared with their source tissue of Oka organ may have contributed to the cellular mitosisarrest. Thus trans-activation of TERT gene may be a candidate in attempts to immortalize in vitro cultured shrimp cells. This work will lay a solid foundation for future studies of the biological functions of telomerase in crustaceans.
端粒酶逆转录酶（TERT）是端粒酶的催化亚基，在端粒酶的活性和生物学功能中起关键作用。在本研究中，我们从中国明对虾中分离并鉴定了TERT基因（MeTERT）的全长cDNA和DNA序列。MeTERT cDNA长度为4239 bp，由一个369 bp的5'UTR、一个3231 bp的开放阅读框（编码1076个氨基酸）和一个639 bp的3'UTR组成。MeTERT的基因组DNA只有两个内含子，类似于甲虫（两个内含子）和家蚕（无内含子）。MeTERT蛋白与其他已知的TERT蛋白仅有5.2 - 7.9%的同源性，但包含N端TEN、RNA结合结构域（TRBD）、逆转录酶（RT）和C端CTE这四个主要的TERT结构域。通过RT-qPCR进行的表达模式分析表明，在所有测试样本中均能检测到MeTERT mRNA转录本，在鳃、糠虾幼体、奥卡器官和卵中的表达水平相对较高，而在肌肉、卵巢、体外培养3天的奥卡器官细胞和心脏中的表达水平较低。与奥卡器官的源组织相比，体外培养3天的奥卡器官原代细胞中MeTERT表达的显著降低可能导致了细胞有丝分裂停滞。因此，TERT基因的反式激活可能是使体外培养的虾细胞永生化的一种候选方法。这项工作将为今后研究端粒酶在甲壳类动物中的生物学功能奠定坚实基础。
