在Saccharomyces cerevisiae中的同翻译mRNA衰变
Wenqian Hu1, Thomas J Sweet, Sangpen Chamnongpol
1Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Nature
|August 25, 2009
概括
使者RNA (mRNA) 衰变发生在核糖体正在积极翻译时,这挑战了需要去除核糖体的想法. 这表明mRNA降解的进化使最终的核糖体能够完成翻译.
科学领域:
- 分子生物学分子生物学
- 基因表达规范 基因表达规范
- 在RNA代谢过程中.
背景情况:
- 稳态信使RNA (mRNA) 的水平是由转录和衰变速率决定的.
- 转录调节是很好的理解,但mRNA衰变机制仍然在很大程度上不清楚.
- 在酵母中,mRNA衰变涉及死亡化,切割和5'-3'外核酶消化.
研究的目的:
- 为了研究核糖体在mRNA衰变途径中的作用.
- 为了确定核糖体解离是否是mRNA降解的先决条件.
- 阐明翻译和mRNA衰变之间的关系.
主要方法:
- 研究了酵母中的mRNA衰变.
- 观察到与活跃翻译核糖体相关的mRNA衰变.
- 分析了与mRNA降解相关的核糖体解离的时间.
主要成果:
- mRNA衰变与活性核糖体翻译同时发生.
- 在mRNA降解开始之前不需要核糖体解离.
- 5'-3'的mRNA降解极性可以确保翻译完成.
结论:
- 主流假设说,核糖体必须在mRNA衰变之前脱离是不正确的.
- mRNA衰变可以继续在积极翻译的转录中进行.
- mRNA降解的过程与翻译的完成有关.
相关概念视频
Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nonsense-mediated mRNA Decay
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
mRNA Stability and Gene Expression
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability
Nonsense-mediated mRNA Decay
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
mRNA Stability and Gene Expression
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability


