注册 登录  
 加关注
   显示下一条  |  关闭
温馨提示!由于新浪微博认证机制调整,您的新浪微博帐号绑定已过期,请重新绑定!立即重新绑定新浪微博》  |  关闭

Bioinformatics home

 
 
 

日志

 
 

miRNA/siRNA/ta-siRNA/ra-siRNA/lsiRNA  

2009-11-12 11:12:23|  分类: Bioinformatics |  标签: |举报 |字号 订阅

  下载LOFTER 我的照片书  |

 Thus far, five classes of sRNAs have been discovered in plants: miRNAs and four types of small interfering RNAs (siRNAs), including trans-acting siRNAs (ta-siRNAs), natural antisense transcript-derived siRNAs (nat-siRNAs), repeat-associated siRNAs (ra-siRNAs),and long siRNA (lsiRNA).

MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are 20-24-nucleotide (nt) noncoding RNAs that repress gene expression through sequence-specific interactions with RNA or DNA . These small RNAs serve as guide molecules for protein complexes that mediate RNA degradation, translational repression, or heterochromatin production. miRNAs and siRNAs are distinguished by the structure of their precursors and by their targets. miRNAs are cleaved from the short, imperfectly paired stem of a much larger foldback transcript and regulate the expression of transcripts to which they may have limited similarity. siRNAs arise from a long, perfectly paired double-stranded RNA (dsRNA) and typically direct the cleavage of transcripts to which they are completely complementary, including the transcript from which they are derived.

 

ta-siRNAs are a plant-speci?cclass of siRNAs, the production of which is initiated by miRNA mediated cleavage of noncoding transcripts. The cleavage products serve as substrates for an RNA-dependent RNA polymerase (RDR6 in Arabidopsis) to generate double-stranded RNAs that are further processed by DCL4 into phased siRNAs(Peragine et al., 2004; Vazquez et al., 2004; Allen et al., 2005;Xie et al., 2005a; Yoshikawa et al., 2005; Axtell et al., 2006). Arabidopsis ta-siRNAs regulate the juvenile-to-adult vegetative phase change (Adenot et al., 2006; Fahlgren et al., 2006; Garciaet al., 2006; Hunter et al., 2006).

 

plant also contain an abundant class of ;24-nucleotide ra-siRNAs derived from transposons and repetitive elements. The biogenesis of ra-siRNAs requires activities of DCL3, RDR2, and Pol IV, a plant-speci?c DNA-dependent RNA polymerase. ra-siRNAs play a role in the methylation and silencing of many transposons and also some genes that are adjacent to repeats (Henderson and Jacobsen, 2007; Zaratiegui et al., 2007). All types of sRNAs interact with AGO proteins to exert their functions.

 

 

  评论这张
 
阅读(1001)| 评论(0)
推荐 转载

历史上的今天

在LOFTER的更多文章

评论

<#--最新日志,群博日志--> <#--推荐日志--> <#--引用记录--> <#--博主推荐--> <#--随机阅读--> <#--首页推荐--> <#--历史上的今天--> <#--被推荐日志--> <#--上一篇,下一篇--> <#-- 热度 --> <#-- 网易新闻广告 --> <#--右边模块结构--> <#--评论模块结构--> <#--引用模块结构--> <#--博主发起的投票-->
 
 
 
 
 
 
 
 
 
 
 
 
 
 

页脚

网易公司版权所有 ©1997-2017