由德州农工大学和辛辛那提大学的科学家组成的研究小组发现,在DNA结构和与端粒的关系,以及它们如何影响细胞老化和癌症方面,一种常见的杂草-拟南芥和人类的癌细胞能够提供一些非常特殊的信息。
在这项研究中,小组人员检测了拟南芥(Arabidopsis)的端粒,发现了一套新的重要的端粒蛋白。然后在人类研究中,他们发现该蛋白可能有助于理解人类的癌症和细胞老化。该研究结果发布在近期的Molecular Cell上。
端粒位于每个染色体的末端,由DNA和蛋白质组成。其主要的功能是保护染色体的末端,它们同样在细胞分裂中具有重要作用。研究人员相信在细胞寿命方面端粒也承担了重要的角色。
研究人员发现移除植物的端粒蛋白会导致染色体末端与末端相连,对植物生长产生重要影响。此外,在移除人类癌细胞的一个蛋白后,他们发现这引起了广泛的DNA损坏,导致一些端粒的完全丢失。研究人员介绍说,端粒在保护染色体方面具有重要作用,其帽子能够阻止染色体并合。同样端粒的长度也决定了细胞分裂的次数。
然而,科学家还不能完全理解端粒的帽子结构如何阻止染色体连接或调控端粒长度。这是一个重要的问题,因为端粒如果出问题会导致疾病发生,比如癌症,过早老化,再生障碍性贫血,肺纤维化等。这个新发现的蛋白复合物能保护端粒的帽子结构,或能为人类疾病的相关研究开辟新的道路。(生物谷Bioon.com)
近期热点:
端粒及端粒酶研究获得09年诺贝尔生理学或医学奖
童坦君院士、谭铮研究员:端粒研究方兴未艾
端粒详解:
端粒和端粒酶的发现历程
周金秋研究员:端粒——稳定线性染色体的末端结构
生物谷推荐原始出处:
Molecular Cell, 23 October 2009 doi:10.1016/j.molcel.2009.09.017
Conserved Telomere Maintenance Component 1 Interacts with STN1 and Maintains Chromosome Ends in Higher Eukaryotes
Yulia V. Surovtseva1, 3, Dmitri Churikov2, Kara A. Boltz1, Xiangyu Song1, Jonathan C. Lamb1, Ross Warrington1, 4, Katherine Leehy1, Michelle Heacock1, 5, Carolyn M. Price2, , and Dorothy E. Shippen1, ,
1 Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
2 Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, OH 45267, USA
3 Present address: Department of Pathology, Yale University School of Medicine, P.O. Box 208023, New Haven, CT 06520-8023, USA
4 Present address: Department of Pharmacology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center Dallas, TX 75390, USA
5 Present address: Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
Orthologs of the yeast telomere protein Stn1 are present in plants, but other components of the Cdc13/Stn1/Ten1 (CST) complex have only been found in fungi. Here we report the identification of conserved telomere maintenance component 1 (CTC1) in plants and vertebrates. CTC1 encodes an ~140 kDa telomere-associated protein predicted to contain multiple OB-fold domains. Arabidopsis mutants null for CTC1 display a severe telomere deprotection phenotype accompanied by a rapid onset of developmental defects and sterility. Telomeric and subtelomeric tracts are dramatically eroded, and chromosome ends exhibit increased G overhangs, recombination, and end-to-end fusions. AtCTC1 both physically and genetically interacts with AtSTN1. Depletion of human CTC1 by RNAi triggers a DNA damage response, chromatin bridges, increased G overhangs, and sporadic telomere loss. These data indicate that CTC1 participates in telomere maintenance in diverse species and that a CST-like complex is required for telomere integrity in multicellular organisms.