甲基磁化易引发家庭癌症
文章来源:未知 文章作者:enread 发布时间:2011-08-17 03:05 字体: [ ]  进入论坛
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Medical researchers have discovered a new type of mechanism1(机制,原理) causing cancer susceptibility, showing that tiny changes in some anti-cancer genes3 can act as magnets to attract modifying "biochemical tags," effectively switching them off and predisposing(素因性的) families to an increased risk of the disease. The study and its findings are reported in the leading international journal Cancer Cell.

The researchers, from the University of New South Wales (UNSW), believe a tiny spelling mistake involving a single letter in the DNA4 sequence near the start of the genes is what attracts the biochemical tag -- known as methylation(甲基化) .

This biochemical tag directly impacts on our DNA, by switching genes off.

"Methylation sits on top of our DNA, and provides the instructions to turn the gene2 off," explains study co-leader, Dr Megan Hitchins, from UNSW's Lowy Cancer Research Centre.

In one well-known cause of hereditary5(遗传的) cancer, changes in the cancer-prevention gene MLH1 are passed from parent to child creating up to 80 percent risk of developing bowel6, uterine(子宫的) and other cancers. However, some families with hereditary cancer have no spelling mistakes in MLH1, but instead have methylation sitting on the gene.

"When the methylation attaches to the MLH1 gene in these families, it causes it to be completely switched off and as a consequence cancer develops," says study co-leader and head of the adult cancer program at the Lowy Cancer Research Centre, Professor Robyn Ward7. "But until now, we did not understand how these methylation tags were being passed from parent to child."

In the study the researchers looked at three generations of a large family, who had cancer at a young age, but in whom no spelling mistakes typical of this hereditary cancer syndrome8 had been found. Strikingly several members of the family from all generations had methylation tags on their gene.

"In this family, biochemical tags attached to the MLH1 gene were present in all three generations. This was intriguing9(有趣的) since these markers are usually removed during the production of eggs and sperm10," Dr Hitchins said.

"What we found was that a subtle change near the gene was acting11 like a magnet to attract methylation. So it was not the methylation itself that was being passed from parent to child, but rather the DNA change, and this acted as a methyl magnet," she said.

The methylation was cleared away in the sperm and eggs and then recreated in each new generation, the researchers said.

Professor Ward said the discovery pinpointed12 the cause of cancer in this family and it offered new options for genetic13 diagnosis14, counselling and early interventions15 in other families at risk of hereditary cancers.

The team is also exploring the use of certain drugs to clear away the methylation in cancer to switch the anti-cancer genes back on again. In the future these drugs may be used to create a more targeted approach to cancer treatment and possibly prevention.

Other researchers involved in this study were the Genetic Services of Western Australia and School of Paediatrics and Child Health, University of Western Australia.



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1 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。
2 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
3 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
4 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。
5 hereditary fQJzF     
adj.遗传的,遗传性的,可继承的,世袭的
参考例句:
  • The Queen of England is a hereditary ruler.英国女王是世袭的统治者。
  • In men,hair loss is hereditary.男性脱发属于遗传。
6 bowel Bszzy     
n.肠(尤指人肠);内部,深处
参考例句:
  • Irritable bowel syndrome seems to affect more women than men.女性比男性更易患肠易激综合征。
  • Have you had a bowel movement today?你今天有排便吗?
7 ward LhbwY     
n.守卫,监护,病房,行政区,由监护人或法院保护的人(尤指儿童);vt.守护,躲开
参考例句:
  • The hospital has a medical ward and a surgical ward.这家医院有内科病房和外科病房。
  • During the evening picnic,I'll carry a torch to ward off the bugs.傍晚野餐时,我要点根火把,抵挡蚊虫。
8 syndrome uqBwu     
n.综合病症;并存特性
参考例句:
  • The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
  • Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。
9 intriguing vqyzM1     
adj.有趣的;迷人的v.搞阴谋诡计(intrigue的现在分词);激起…的好奇心
参考例句:
  • These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
  • It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》
10 sperm jFOzO     
n.精子,精液
参考例句:
  • Only one sperm fertilises an egg.只有一个精子使卵子受精。
  • In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中,一个精子使一个卵子受精。
11 acting czRzoc     
n.演戏,行为,假装;adj.代理的,临时的,演出用的
参考例句:
  • Ignore her,she's just acting.别理她,她只是假装的。
  • During the seventies,her acting career was in eclipse.在七十年代,她的表演生涯黯然失色。
12 pinpointed e23273e2459d3a2f113ef7cdb8d1c728     
准确地找出或描述( pinpoint的过去式和过去分词 ); 为…准确定位
参考例句:
  • His refusal to help simply pinpointed his cowardice. 他拒绝帮助正显示他的胆小。
  • Computers pinpointed where the shells were coming from. 计算机确定了炮弹发射的位置。
13 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
14 diagnosis GvPxC     
n.诊断,诊断结果,调查分析,判断
参考例句:
  • His symptoms gave no obvious pointer to a possible diagnosis.他的症状无法作出明确的诊断。
  • The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做一次彻底的调查分析。
15 interventions b4e9b73905db5b0213891229ce84fdd3     
n.介入,干涉,干预( intervention的名词复数 )
参考例句:
  • Economic analysis of government interventions deserves detailed discussion. 政府对经济的干预应该给予充分的论述。 来自辞典例句
  • The judge's frequent interventions made a mockery of justice. 法官的屡屡干预是对正义的践踏。 来自互联网
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