端粒和端粒酶与肝细胞的永生化

目的：端粒是位于真核细胞染色体末端的蛋白-DNA复合体，保护染色体完整性和稳定性。端粒酶是一种特殊的细胞核蛋白反转录酶，能以自身的RNA为模板，反转录合成端粒DNA序列，添加到染色体来端。端粒酶介导的端粒延长作为细胞中端粒缩短的主要补偿机制，对正常细胞以及肿瘤细胞延长分裂代数起着重要作用、分化良好并具有肝脏正常合成代谢功能的永生化肝细胞在生物医学研究，尤其是肝细胞移植、生物人工肝支持治疗以及药理学和毒理学研究方面具有广泛的应用前景。 资料来源：应用计算机检索Pubmed数据库1990—01／2005—12有关端粒。端粒酶和肝细胞永生化的文章，检索词“telomere，telomerase，hepatocyte，immortalization”，限定文章语言种类为English。同时计算机检索中国期刊全文数据库、万方数据库1994-01／2005—12期间的相关文章，检索词“端粒、端粒酶、永生化、肝细胞”，限定文章语言种类为中文。 资料选择：纳入标准：（1）有关端粒和端粒酶结构和功能的研究文献：②有关端粒、端粒酶与肝细胞永生化相关性的文献：排除标准：重复研究。 资料提炼：共收集到32篇有关端粒、端粒酶与肝细胞永生化相关性的文献，查找全文，从中选取14篇作为主要参考文献。 资料综合：将所选文献资料按照以下顺序归纳总结：①端粒的结构和功能：端粒是指位于真核细胞染色体末端的一种特殊结构，由富含G的DNA重复序列与端粒结合蛋白所构成的一种蛋白-DNA复合体，它既可保护染色体不受核酸酶的破坏，又避免了因DNA粘性末端的裸露而发生的染色体融合．②端粒酶的结构和功能：端粒酶是一种RNA依赖的DNA聚合酶，能以自身的RNA为模板，反转录合成端粒DNA序列，添加到染色体末端，以补偿细胞分裂时端粒DNA缩短，使细胞克服危机期，?

Telomere, telomerase and hepatocyte immortalization

OBJECTIVE： Talomere is one protein-DNA complex found at ends of eukaryotic chromosomes. An adequate talomerelength is required for chromosome integrality and stability. Telomerase is a specialized cellular ribonucleoprotein reverse transeriptase, which can synthesizes the telomeric DNA onto the distal end.of the chromosome using itself RNA subunit as a template. Prolonging the talomere length mediated by activating telomerase, as the main reimbursement mechanism of telomere shortening, is essential for extending the segmenting algebra of nounal somatic cells and tumors. Immortalized hepatocyte cells with good differentiation and liver nounal anabolism function will be broadly applicated in biomedicine, especially for hepatoeyte transplantation, bioartificial liver support, pharmacology and toxicology.
DATA SOURCES： The relevant articles on the telomere, telomerase and hepatoeyte immortalization published in English were searched in Pubmed Database between January 1990 and December 2005 using the key words of ＂telomere, telomerase, hepatocyte, immortalization＂. Meanwhile, the Chinese articles between January 1994 and December 2005 were searched in China Journal Full-text Database （CJFD） and Wanfang Database with the same key words.
STUDY SELECTION： Inclusion criteria：（1）The structure and function of tetomere and telomerase. （2）The relationship of telomere and telomerase with hepatocyte immortalization. Exclusion criteria： Repetitive studies.
DATA EXTRACTION： There were totally 32 articles about the relationship among telomere, telomerase and hepatocyte immortalization were collected for the full-texts, and 14 ones were taken as main references.
DATA SYNTHESIS： The selected data were summarized in the following order： （1）The structure and function of telomere： Telomere is one specific structure located at ends of eukaryotic chromosomes, and also one protein- DNA complex consisted of DNA repeated sequence and telomere conjugated protein. Telomere can not only prevent chro