新浪登录
腾讯登录Nature：发现介导X染色体失活的新RNA
| 导读 | 在雌性哺乳动物中，两条X染色体需要随机失活一条，以确保雌雄个体有同等剂量的X染色体转录产物。以往的研究中，研究者发现非编码RNAXist介导真哺乳亚纲动物X染色体失活，但在后兽亚纲动物中不存在Xist。因此后兽亚纲动物的X染色体失活机制是什么成为困扰科学界已久的谜题。
<!--more-->
本文中，研究者利用短尾猊作为研究对象，发现Rsx (RNA-on-the-sile... |
在雌性哺乳动物中，两条X染色体需要随机失活一条，以确保雌雄个体有同等剂量的X染色体转录产物。以往的研究中，研究者发现非编码RNAXist介导真哺乳亚纲动物X染色体失活，但在后兽亚纲动物中不存在Xist。因此后兽亚纲动物的X染色体失活机制是什么成为困扰科学界已久的谜题。
<!--more-->
本文中，研究者利用短尾猊作为研究对象，发现Rsx (RNA-on-the-silent X) 介导X染色体失活。Rsx只在雌性动物体内表达，它从X染色体上转录，并能够包裹在失活的X染色体上。在雌性动物的生殖细胞中，即两条X染色体都处于活化状态的细胞，Rsx不表达。此外，研究者在小鼠胚胎干细胞中表达Rsx，发现可通过顺式调节引起基因沉默。
该研究阐明了后兽亚纲动物的X染色体沉默机制，是对哺乳动物X染色体沉默机制的有利补充。
<div id="ztload">
<div>
<div>
<img id="cover-image" src="http://www.bioon.com/biology/UploadFiles/201206/20120614210443482.jpg" alt="" width="116" />
<a title="" href="http://dx.doi.org/10.1038/nature11171" target="_blank">doi:10.1038/nature11171</a>
PMC:
PMID:
</div>
<div>
<br/><strong><em>Rsx</em> is a metatherian RNA with <em>Xist</em>-like properties in X-chromosome inactivation</strong><br/>
Jennifer Grant, Shantha K. Mahadevaiah, Pavel Khil, Mahesh N. Sangrithi, Hélène Royo, Janine Duckworth, John R. McCarrey, John L. VandeBerg, Marilyn B. Renfree, Willie Taylor, Greg Elgar, R. Daniel Camerini-Otero, Mike J. Gilchrist & James M. A. Turner
In female (XX) mammals, one of the two X chromosomes is inactivated to ensure an equal dose of X-linked genes with males (XY)1. X-chromosome inactivation in eutherian mammals is mediated by the non-coding RNA Xist2. Xist is not found in metatherians3 (marsupials), and how X-chromosome inactivation is initiated in these mammals has been the subject of speculation for decades4. Using the marsupial Monodelphis domestica, here we identify Rsx (RNA-on-the-silent X), an RNA that has properties consistent with a role in X-chromosome inactivation. Rsx is a large, repeat-rich RNA that is expressed only in females and is transcribed from, and coats, the inactive X chromosome. In female germ cells, in which both X chromosomes are active, Rsx is silenced, linking Rsx expression to X-chromosome inactivation and reactivation. Integration of an Rsx transgene on an autosome in mouse embryonic stem cells leads to gene silencing in cis. Our findings permit comparative studies of X-chromosome inactivation in mammals and pose questions about the mechanisms by which X-chromosome inactivation is achieved in eutherians.
<br/>来源：生物谷
</div>
</div>
</div>
<!--more-->
本文中，研究者利用短尾猊作为研究对象，发现Rsx (RNA-on-the-silent X) 介导X染色体失活。Rsx只在雌性动物体内表达，它从X染色体上转录，并能够包裹在失活的X染色体上。在雌性动物的生殖细胞中，即两条X染色体都处于活化状态的细胞，Rsx不表达。此外，研究者在小鼠胚胎干细胞中表达Rsx，发现可通过顺式调节引起基因沉默。
该研究阐明了后兽亚纲动物的X染色体沉默机制，是对哺乳动物X染色体沉默机制的有利补充。
<div id="ztload">
<div>
<div>
<img id="cover-image" src="http://www.bioon.com/biology/UploadFiles/201206/20120614210443482.jpg" alt="" width="116" />
<a title="" href="http://dx.doi.org/10.1038/nature11171" target="_blank">doi:10.1038/nature11171</a>
PMC:
PMID:
</div>
<div>
<br/><strong><em>Rsx</em> is a metatherian RNA with <em>Xist</em>-like properties in X-chromosome inactivation</strong><br/>
Jennifer Grant, Shantha K. Mahadevaiah, Pavel Khil, Mahesh N. Sangrithi, Hélène Royo, Janine Duckworth, John R. McCarrey, John L. VandeBerg, Marilyn B. Renfree, Willie Taylor, Greg Elgar, R. Daniel Camerini-Otero, Mike J. Gilchrist & James M. A. Turner
In female (XX) mammals, one of the two X chromosomes is inactivated to ensure an equal dose of X-linked genes with males (XY)1. X-chromosome inactivation in eutherian mammals is mediated by the non-coding RNA Xist2. Xist is not found in metatherians3 (marsupials), and how X-chromosome inactivation is initiated in these mammals has been the subject of speculation for decades4. Using the marsupial Monodelphis domestica, here we identify Rsx (RNA-on-the-silent X), an RNA that has properties consistent with a role in X-chromosome inactivation. Rsx is a large, repeat-rich RNA that is expressed only in females and is transcribed from, and coats, the inactive X chromosome. In female germ cells, in which both X chromosomes are active, Rsx is silenced, linking Rsx expression to X-chromosome inactivation and reactivation. Integration of an Rsx transgene on an autosome in mouse embryonic stem cells leads to gene silencing in cis. Our findings permit comparative studies of X-chromosome inactivation in mammals and pose questions about the mechanisms by which X-chromosome inactivation is achieved in eutherians.
<br/>来源：生物谷
</div>
</div>
</div>
还没有人评论，赶快抢个沙发