生物谷：瑞典卡罗林斯卡医学院日前说，他们研究发现了受损ＤＮＡ（脱氧核糖核酸）的修复机理，这将有助于癌症研究。
卡罗林斯卡医学院的卡米拉·肖格伦在１４日向记者提供的资料中说，细胞分裂前，一个ＤＮＡ分子将会被复制成两个，并通过一种叫做Ｃｏｈｅｓｉｎ的物质黏合在一起。一旦两个ＤＮＡ分子分开太早，新生成的细胞中的染色体（ＤＮＡ分子的主要载体）数量就可能出现异常，正像很多肿瘤细胞的染色体数量异常一样。
瑞典研究人员发现，与通常的认识不同，细胞会使用Ｃｏｈｅｓｉｎ来修复受损的ＤＮＡ链。肖格伦说，这项发现涉及到细胞最基本的工作机理，对癌症研究无疑具有重要意义。
这项研究刊登在１３日出版的美国《科学》杂志上。（新华网）
原始出处:
Science 13 July 2007:
Vol. 317. no. 5835, pp. 242 - 245
DOI: 10.1126/science.1140649
Postreplicative Formation of Cohesion Is Required for Repair and Induced by a Single DNA Break
Lena Ström,1 Charlotte Karlsson,1 Hanna Betts Lindroos,1 Sara Wedahl,1 Yuki Katou,2 Katsuhiko Shirahige,2 Camilla Sjögren1*
Sister-chromatid cohesion, established during replication by the protein complex cohesin, is essential for both chromosome segregation and double-strand break (DSB) repair. Normally, cohesion formation is strictly limited to the S phase of the cell cycle, but DSBs can trigger cohesion also after DNA replication has been completed. The function of this damage-induced cohesion remains unknown. In this investigation, we show that damage-induced cohesion is essential for repair in postreplicative cells in yeast. Furthermore, it is established genome-wide after induction of a single DSB, and it is controlled by the DNA damage response and cohesin-regulating factors. We thus define a cohesion establishment pathway that is independent of DNA duplication and acts together with cohesion formed during replication in sister chromatid–based DSB repair.
1 Department of Cell and Molecular Biology, Karolinska Institute, 171 77 Stockholm, Sweden.
2 Gene Research Centre, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, 226-8501 Yokohama, Japan.
* To whom correspondence should be addressed. E-mail: camilla.sjogren@ki.se
