研究人员发现前所未知的DNA甲基化模式
文章来源:未知 文章作者:meng 发布时间:2010-06-03 01:00 字体: [ ]  进入论坛
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A previously1 unknown pattern in DNA2 methylation(甲基化) - an event that affects cell function by altering gene3 expression – has been uncovered for the first time by stem cell researchers at UCLA, a finding that could have implications(含意,启示) in preventing some cancers and correcting defects in human stem cell lines. The team of scientists discovered a relationship between DNA methylation and the positioning of nucleosomes(核小体) , which compact and regulate access to DNA in the nucleus4 of a cell. The discovery was made using high-throughput(生产量,生产能力) DNA sequencing to study the sites on DNA where high levels of methylation were occurring, said Matteo Pellegrini and Steve Jacobsen, researchers with the Broad Stem Cell Research Center at UCLA and senior co-authors of the study.

The study appeared Sun., May 30, 2010 in the early online edition of the peer-reviewed journal Nature.

The processes required for the survival of a cell depend on the cell's ability to store and read the genetic5 information encoded in its DNA. Packaging the long DNA into a tiny nucleus is complicated because the DNA still needs to be accessible to the cell's molecular6 machinery7. The molecules8 that compact DNA are called the nucleosome core particles. Each one has about 147 base pairs of DNA wrapped around it. This interaction forms a sort of scaffolding(脚手架) for compaction9 of the long DNA polymer(聚合体) , while allowing it to be accessible for events such as methylation.

DNA methylation is important in regulating genes10 that play a role in the differentiation11 of embryonic12(胚胎的) stem cells and in the development of some cancers, Jacobsen said.

"Changes in DNA methylation are behind a lot of what makes a stem cell a stem cell. As the cell differentiates13, the DNA methylation tends to change. One aspect of understanding methylation is understanding its pattern and how it's laid out within the cell," said Jacobsen, a professor of molecular, cell and developmental biology and a Howard Hughes Medical Institute investigator14.

In this study, the UCLA team found that the DNA wrapped around nucleosomes is more highly methylated than flanking DNA, which links adjacent DNA/nucleosome complexes.

"These results indicate that nucleosome positioning influences DNA methylation patterning throughout the genome and that DNA methyltransfereases (the enzymes15 that methylates DNA) preferentially(优先地,优惠地) target nucloesome-bound DNA," said Pellegrini, an associate professor of molecular, cell and developmental biology and an informatics(信息学,情报学) expert.

The work was initially16 done in Arabidopsis(拟南芥) , a mustard weed commonly used in plant research. Once the DNA methylation and nucleosome positioning patterns emerged, they repeated the work in human stem cells. Pellegrini and Jacobsen found similar patterns in the human stem cells.

One of the most important, unknown aspects of DNA methylation, Jacobsen said, is how the cell determines where the event occurs, and the pattern of nucleosome positions has emerged as an important determinant of methylation.

The findings could have implications in fighting cancer because DNA methylation patterns go awry17(扭曲的,走样的) in cancer, often causing tumor18 suppressor genes to switch off. The more scientists know about the cellular19 mechanisms20 that lay down the correct DNA methylation patterns, the more that process can be manipulated. In the future, this type of research may lead to techniques that result in the ability to control the patterns that go awry and lead to cancer, thus preventing a malignancy(恶意,恶性) .

And because DNA methylation is important in stem cell differentiation, this knowledge could lead to ways to correct defects in stem cells lines in the future.



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1 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
2 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。
3 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。
4 nucleus avSyg     
n.核,核心,原子核
参考例句:
  • These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
  • These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。
5 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。
6 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。
7 machinery CAdxb     
n.(总称)机械,机器;机构
参考例句:
  • Has the machinery been put up ready for the broadcast?广播器材安装完毕了吗?
  • Machinery ought to be well maintained all the time.机器应该随时注意维护。
8 molecules 187c25e49d45ad10b2f266c1fa7a8d49     
分子( molecule的名词复数 )
参考例句:
  • The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
9 compaction MXKyh     
n.压紧
参考例句:
  • Large-scale consolidation and compaction of soil were responsible for the destruction.大部分破坏都是由于土壤的大规模固结和压密所造成的。
  • Soil compaction may limit horizontal root extension.土壤的紧密度能限制水平根的扩展。
10 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
11 differentiation wuozfs     
n.区别,区分
参考例句:
  • There can be no differentiation without contrast. 有比较才有差别。
  • The operation that is the inverse of differentiation is called integration. 与微分相反的运算叫做积分。
12 embryonic 58EyK     
adj.胚胎的
参考例句:
  • It is still in an embryonic stage.它还处于萌芽阶段。
  • The plan,as yet,only exists in embryonic form.这个计划迄今为止还只是在酝酿之中。
13 differentiates e1a5ca2c9946ac040edc6427341f59db     
区分,区别,辨别( differentiate的第三人称单数 ); 区别对待; 表明…间的差别,构成…间差别的特征
参考例句:
  • This genus of plants differentiates into many species. 这种植物可分为许多种类。
  • Our fax machine differentiates between an incoming fax signal and a voice call. 我们的传真机能区分接收传真信号和语音信号。
14 investigator zRQzo     
n.研究者,调查者,审查者
参考例句:
  • He was a special investigator for the FBI.他是联邦调查局的特别调查员。
  • The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
15 enzymes 7881ad8ce9c83424f7874e70266ed2d8     
n. 酶,酵素
参考例句:
  • It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
  • Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。
16 initially 273xZ     
adv.最初,开始
参考例句:
  • The ban was initially opposed by the US.这一禁令首先遭到美国的反对。
  • Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。
17 awry Mu0ze     
adj.扭曲的,错的
参考例句:
  • She was in a fury over a plan that had gone awry. 计划出了问题,她很愤怒。
  • Something has gone awry in our plans.我们的计划出差错了。
18 tumor fKxzm     
n.(肿)瘤,肿块(英)tumour
参考例句:
  • He was died of a malignant tumor.他死于恶性肿瘤。
  • The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。
19 cellular aU1yo     
adj.移动的;细胞的,由细胞组成的
参考例句:
  • She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
  • Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。
20 mechanisms d0db71d70348ef1c49f05f59097917b8     
n.机械( mechanism的名词复数 );机械装置;[生物学] 机制;机械作用
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。 来自《简明英汉词典》
  • He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》
TAG标签: DNA gene cell methylation
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