一直以来，科学家认为，端粒（Telomeres）的唯一作用在于保护DNA免受磨损。瑞士科学家最新研究发现，端粒的作用不仅如此，它还能作为合成RNA的模板。相关论文10月4日在线发表于《科学》上。
每次染色体进行复制的时候，末端的DNA总是会发生丢失。为了防止重要遗传信息的遗失，端粒会“牺牲”自我，贡献出自己的片断。长期下来，端粒就会越来越短。很多科学家相信，端粒的长短与细胞的寿命有着重要的联系。很多癌细胞之所以能够长久生存，就是因为它们能够维持较长的端粒。另外，端粒还能够阻止旁边的DNA合成RNA。
在最新的研究中，瑞士实验癌症研究所（ISREC）的Joachim Lingner和同事在研究一个与RNA降解有关的蛋白时发现，该蛋白与端粒相联系。随后，他们在端粒附近发现了丛生的RNA。
法国原子能委员会的分子生物学家Laure Sabatier说，这是一项重大的突破，从来没有人会想过，端粒能够作为合成RNA的DNA模板。
Lingner表示，目前尚不清楚该发现是否能够为癌症治疗提供新途径，端粒附近RNA的作用也还不明了。他说，实验表明，当端粒附近RNA水平升高，端粒的丢失速度会加快。但这二者之间是否直接相关还有待研究。（科学网 梅进/编译）
原始出处:
Published Online October 4, 2007
Science DOI: 10.1126/science.1147182
Submitted on June 28, 2007
Accepted on September 17, 2007
Telomeric Repeat–Containing RNA and RNA Surveillance Factors at Mammalian Chromosome Ends
Claus M. Azzalin 1, Patrick Reichenback 1, Lela Khoriauli 2, Elena Giulotto 2, Joachim Lingner 1*
1 Swiss Institute for Experimental Cancer Research (ISREC), CH-1066 Epalinges, Switzerland.; School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.; "Frontiers in Genetics" National Centre for Competence in Research (NCCR), CH-1211 Geneva, Switzerland.
2 University of Pavia, Department of Genetics and Microbiology, 27100 Pavia, Italy.
* To whom correspondence should be addressed.
Joachim Lingner , E-mail: joachim.lingner@isrec.ch
Telomeres, the DNA-protein complexes located at the end of linear eukaryotic chromosomes, are essential for chromosome stability. Until now, telomeres have been considered to be transcriptionally silent. We demonstrate here that mammalian telomeres are transcribed into telomeric repeat containing RNA (TERRA). TERRA molecules are heterogeneous in length, are transcribed from several subtelomeric loci towards chromosome ends and localize to telomeres. We also show that Suppressors with Morphogenetic Defects in Genitalia (SMG) proteins, which are effectors of nonsense mediated RNA decay, are enriched at telomeres in vivo, negatively regulate TERRA association with chromatin and protect chromosome ends from telomere loss. Thus, telomeres are actively transcribed into TERRA, and SMG factors represent a molecular link between TERRA regulation and maintenance of telomere integrity.
