共查询到19条相似文献，搜索用时 156 毫秒
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端粒酶和细胞衰老 总被引：3，自引：1，他引：2
端粒是真核细胞染色体末端的一种特殊结构 ,由端粒 DNA和端粒蛋白质组成。端粒DNA是富含 G的高度保守的重复核苷酸序列 ,人和其他哺乳动物的端粒 DNA序列均由 5′-3′,方向 (TTAGGG) n 反复串联组成 ,它参与 DNA复制 ,对维持染色体的稳定和完全复制有重要作用。正常动物细胞 DNA的端粒随着细胞分裂而缩短 ,当缩短到一定长度时细胞将停止增殖并死亡。细胞中的端粒酶在正常细胞不表达 ,只在生殖细胞、干细胞和肿瘤细胞中表达。文章介绍了细胞衰老的细胞生物学机制、端粒酶和细胞衰老的关系 ,讨论了端粒酶和克隆动物的早衰现象的关系 相似文献
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端粒酶是真核生物细胞染色体末端富含G的简单重复结构。在生理状况下,随着细胞分裂次数增加,端粒在复制分裂过程中将逐渐丢失碱基,从而致使端粒逐渐缩短。当端粒缩短至一定长度时细胞将进人生长停止衰老死亡阶段,即出现细胞的凋亡。最近几年来,人们研究发现一种端粒酶能够逆转录合成端粒DNA,并添加到端粒从而达到防止端粒缩短,维持端粒的长度,进而保持染色体的稳定性。由于大多数生物体细胞生理状态下, 相似文献
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端粒和端粒酶的研究进展 总被引：7，自引：4，他引：3
端粒和端粒酶是现代生物学研究的热点,端粒封闭了染色体的末端并维持了染色体的稳定性,端粒的缺失会引起染色体融合并导致细胞的衰老及死亡.端粒酶的活化可延长染色体末端DNA,维持基因组的稳定.并且端粒酶活性的异常表达又会引起细胞永生化或转化成癌细胞.因此端粒和端粒酶的结构和功能的研究对于治疗肿瘤和控制细胞寿命有着极其重要的意义.文章综述了端粒和端粒酶的结构和功能,及其与细胞老化的关系,并在此基础之上展望了端粒酶在抑制肿瘤、抗衰老等方面的应用. 相似文献
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端粒位于真核生物染色体末端,它对维持染色体结构具有非常重要的意义。端粒酶能够以自身的RNA序列为模板反转录合成端粒的重复DNA序列,对端粒长度的维持以及哺乳动物的生长发育具有重要的作用。本文主要对端粒和端粒酶的结构和功能,以及它们在哺乳动物发育过程中的重要作用进行阐述。1端粒、端粒酶的结构和功能1.1端粒的结构和功能1.1.1端粒的结构:端粒位于真核生物染色体末端 相似文献
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端粒和端粒酶与衰老关系的研究进展 总被引：6，自引：0，他引：6
端粒是存在于线性染色体末端的一段特殊的DNA－蛋白质复合物，由于末端不能复制，正常体细胞随着细胞分裂的进行而逐渐丢失端粒序列，导致细胞老化和死亡。端粒酶是维持端粒长度的一种特殊的DNA聚合酶，在细胞的增殖、衰老及永生中起重要作用。本文就端粒和端粒酶及其与衰老的作一综述。 相似文献
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端粒位于真核染色体末端，是稳定染色体末端的重要元件。端粒酶（TER）是一种特殊的细胞核蛋白（RNP）反转录酶（RT），其核心酶包括蛋白亚基和RNA元件。在DNA复制过程中的端粒丢失可以被有活性的端粒酶补偿回来。哺乳动物端粒酶在发育中受调控，端粒的重编程可能是由于早期胚胎不同时期的端粒酶活性而造成的，因此，研究胚胎发育早期端粒和端粒酶重编程是非常重要的。本文对端粒和端粒酶的结构和功能，及其与哺乳动物早期胚胎发育的关系进行了综述．并在此基础上展望了端粒和端粒酶在克隆动物胚胎发育上的基础作用。 相似文献
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Effects of donor cells’ sex on nuclear transfer efficiency and telomere lengths of cloned goats 
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下载免费PDF全文 H‐j Liu H Peng C‐c Hu X‐y Li J‐l Zhang Z Zheng W‐c Zhang 《Reproduction in domestic animals》2016,51(5):789-794
The aim of this study was to investigate the effects of donor cells’ sex on nuclear transfer efficiency and telomere length of cloned goats from adult skin fibroblast cells. The telomere length of somatic cell cloned goats and their offspring was determined by measuring their mean terminal restriction fragment (TRF) length. The result showed that (i) reconstructed embryos with fibroblast cells from males Boer goats obtained significantly higher kids rate and rate of live kids than those of female embryos and (ii) the telomere lengths of four female cloned goats were shorter compared to their donor cells, but five male cloned goats had the same telomere length with their donor cells, mainly due to great variation existed among them. The offspring from female cloned goats had the same telomere length with their age‐matched counterparts. In conclusion, the donor cells’ sex had significant effects on nuclear transfer efficiency and telomere lengths of cloned goats. 相似文献
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端粒是真核染色体分子末端的DNA区域,是由重复的DNA序列和端粒结合蛋白形成的DNA-蛋白复合物,对于染色体的复制和稳定起着重要作用。近年来研究结果表明,端粒长度的缩短与人类疾病和衰老密切相关。同时,体细胞核移植(somatic cell nuclear transfer,SCNT)作为一种有效的无性生殖手段,越来越多的在科研和生产中得到应用。由于体细胞核移植通常采用体细胞作为核供体细胞,因而供体细胞的端粒长度、核移植后重组胚的端粒在胚胎早期是否会被修复、端粒长度是否有变化等问题,对于研究克隆动物的重编程、发育生物学都有着重要的指导意义。作者将对端粒的结构和端粒长度的机理研究、在克隆哺乳动物中对端粒长度的探索研究,以及近几年来关于端粒方面的一些研究进展加以阐述。 相似文献
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Yazawa M Okuda M Setoguchi A Iwabuchi S Nishimura R Sasaki N Masuda K Ohno K Tsujimoto H 《American journal of veterinary research》2001,62(10):1539-1543
OBJECTIVE: To measure telomere length and telomerase activity in naturally occurring canine mammary gland tumors. SAMPLE POPULATION: 27 mammary gland tumor specimens obtained during resection or necropsy and 12 mammary gland tissue specimens obtained from healthy (control) dogs. PROCEDURE: Telomere length in tissue specimens was measured by use of restriction endonuclease digestion and Southern blot analysis. Telomerase activity was measured by use of a telomeric repeat amplification protocol assay. RESULTS: Telomere length in mammary gland tumors ranged from 11.0 to 21.6 kilobase pairs (kbp; mean +/- SEM, 14.5+/-0.5 kbp) but did not differ among tumor types. Telomeres in mammary gland tumors were slightly shorter than in normal tissue specimens, but telomere length could not be directly compared between groups, because mean age of dogs was significantly different between groups. Age was negatively correlated with telomere length in control dogs but was not significantly correlated with length in affected dogs. Telomerase activity was detected in 26 of 27 mammary gland tumors and in 4 of 12 normal tissue specimens. However, telomerase activity and telomere length were not correlated in tumor specimens. CONCLUSIONS AND CLINICAL RELEVANCE: Telomere length is maintained in canine mammary gland tumors regardless of the age of the affected dog. Measurement of telomere length may be a useful tool for monitoring the in vivo effects of telomerase inhibitors in dogs with tumors. 相似文献
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马立克氏病(MD)是由马立克氏病毒(MDV)引起的鸡淋巴组织增生性传染病,对养禽业危害巨大。MDV线性基因组末端具有与宿主鸡序列相同的端粒重复序列(TMR),这些TMR有助于在潜伏期将MDV基因组整合到宿主端粒区,从而使病毒终生留在宿主体内。整合到宿主端粒对于MDV致病及诱导肿瘤发生至关重要,也能够有效地重新激活整合的病毒基因组。除TMR外,MDV还编码端粒酶RNA亚基(vTR),其与鸡基因组中端粒酶RNA(chTR)具有88%的序列相似性。vTR在病毒生命周期的所有阶段高度表达,增强端粒酶活性并在MDV诱导的肿瘤形成中起重要作用。文章重点介绍MDV基因组TMR序列和TR基因的最新研究进展。 相似文献
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Nasir L 《Veterinary journal (London, England : 1997)》2008,175(2):155-163
In recent years in human oncology the enzyme telomerase has emerged as an ideal target for cancer therapy. This has led to the assessment of telomerase in cancers in companion animals, mainly dogs and these studies confirm that in dogs, like humans, telomere maintenance by telomerase is the primary mechanism by which cancer cells overcome their mortality and extend their lifespan. This review aims to provide an introduction to the biology of telomeres and telomerase and to discuss some of the telomere/telomerase directed therapeutic methodologies currently under development which may be of benefit to the canine cancer patient. 相似文献