电离辐射如何损伤DNA诱发癌症
文章来源:未知 文章作者:enread 发布时间:2016-12-14 07:45 字体: [ ]  进入论坛
(单词翻译:双击或拖选)
For the first time, researchers from the Wellcome Trust Sanger Institute and their collaborators have been able to identify in human cancers two characteristic patterns of DNA1 damage caused by ionising radiation. These fingerprint2 patterns may now enable doctors to identify which tumours3 have been caused by radiation, and investigate if they should be treated differently. Published in Nature Communications today, the results will also help to explain how radiation can cause cancer.
 
Ionising radiation, such as gamma rays, X-rays and radioactive particles can cause cancer by damaging DNA. However, how this happens, or how many tumours are caused by radiation damage has not been known.
 
Previous work on cancer had revealed that DNA damage often leaves a molecular4 fingerprint, known as a mutational5 signature, on the genome of a cancer cell. The researchers looked for mutational signatures in 12 patients with secondary radiation-associated tumours, comparing these with 319 that had not been exposed to radiation.
 
Dr Peter Campbell from the Wellcome Trust Sanger Institute who led the study, said: "To find out how radiation could cause cancer, we studied the genomes of cancers caused by radiation in comparison to tumours that arose spontaneously. By comparing the DNA sequences we found two mutational signatures for radiation damage that were independent of cancer type. We then checked the findings with prostate cancers that had or had not been exposed to radiation, and found the same two signatures again. These mutational signatures help us explain how high-energy radiation damages DNA."
 
One mutational signature is a deletion where small numbers of DNA bases are cut out. The second is called a balanced inversion6, where the DNA is cut in two places, the middle piece spins round, and is joined back again in the opposite orientation7. Balanced inversions8 don't happen naturally in the body, but high-energy radiation could provide enough DNA breaks at the same time to make this possible.
 
Dr Sam Behjati, clinician researcher at the Sanger Institute and the Department of Paediatrics, University of Cambridge, said: "Ionising radiation probably causes all types of mutational damage, but here we can see two specific types of damage and get a sense of what is happening to the DNA. Showers of radiation chop up the genome causing lots of damage simultaneously9. This seems to overwhelm the DNA repair mechanism10 in the cell, leading to the DNA damage we see."


点击收听单词发音收听单词发音  

1 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
2 fingerprint 4kXxX     
n.指纹;vt.取...的指纹
参考例句:
  • The fingerprint expert was asked to testify at the trial.指纹专家应邀出庭作证。
  • The court heard evidence from a fingerprint expert.法院听取了指纹专家的证词。
3 tumours 6654305f758b5b5576a74cb007e8d079     
肿瘤( tumour的名词复数 )
参考例句:
  • Blood vessels develop abnormally in cancer tumours. 在癌肿瘤中血管出现不正常。
  • This apparatus scans patients' brains for tumours. 这台仪器扫描检查病人的脑瘤。
4 molecular mE9xh     
adj.分子的;克分子的
参考例句:
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
5 mutational 93b3db034d33c6e2d1a62fe59e719551     
[医] 突变的
参考例句:
  • These large populations facilitate the detection of rare mutational or recombinational events. 这样的大群体有利于检出稀有的突变或重组子。
  • All sorts of mutational damage to animals' DNA would have occurred. 动物的脱氧核糖核酸可能遭到了各种各样的突变破坏。
6 inversion pRWzr     
n.反向,倒转,倒置
参考例句:
  • But sometimes there is an unusual weather condition called a temperature inversion.但有时会有一种被称作“温度逆增”的不平常的天气状态。
  • And finally,we made a discussion on the problems in the cooperative inversion.最后,对联合反演中存在的问题进行了讨论。
7 orientation IJ4xo     
n.方向,目标;熟悉,适应,情况介绍
参考例句:
  • Children need some orientation when they go to school.小孩子上学时需要适应。
  • The traveller found his orientation with the aid of a good map.旅行者借助一幅好地图得知自己的方向。
8 inversions 5849e5dcb56365f0d87cffcfd9939cdb     
倒置( inversion的名词复数 ); (尤指词序)倒装; 转化; (染色体的)倒位
参考例句:
  • Chromosome breaks may also lead to inversions and translocations. 染色体破裂也可能引起倒位与易位。
  • The males suspected to have induced inversions were later used to build up stocks. 疑有诱发倒位的雄性然后用于建立原种。
9 simultaneously 4iBz1o     
adv.同时发生地,同时进行地
参考例句:
  • The radar beam can track a number of targets almost simultaneously.雷达波几乎可以同时追着多个目标。
  • The Windows allow a computer user to execute multiple programs simultaneously.Windows允许计算机用户同时运行多个程序。
10 mechanism zCWxr     
n.机械装置;机构,结构
参考例句:
  • The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
  • The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。
TAG标签: radiation ionising DNA
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:点击我更换图片