RNA聚合酶II子单元将转录和mRNA衰变与翻译联系起来
Liat Harel-Sharvit1, Naama Eldad, Gal Haimovich
1Department of Molecular Microbiology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 31096, Israel.
Cell
|November 16, 2010
概括
在酵母中,Rpb4/7异构体将核转录与细胞质翻译联系在一起. 这种蛋白质复合体通过与RNA聚合酶II和翻译因子相互作用来协调基因表达.
科学领域:
- 分子生物学分子生物学
- 酵母遗传学 酵母遗传学
- 基因表达规范 基因表达规范
背景情况:
- 细胞的转录和翻译发生在单独的细胞区内,对它们的交叉通话的理解有限.
- 酵母蛋白Rpb4p和Rpb7p形成了一个异构体,在细胞核和细胞质之间穿.
- Rpb4/7参与转录和mRNA衰变途径.
研究的目的:
- 调查真核生物中转录和翻译机械之间的功能关系.
- 阐明Rpb4/7异构体在基因表达中的作用.
- 提出一种模型,说明转录和翻译在真核细胞中是如何结合的.
主要方法:
- 共同免疫沉以检测物理相互作用.
- 功能性测试以评估翻译启动效率.
- 在酵母中分析Rpb4/7异体聚合物局部化和功能.
主要成果:
- 在物理和功能上,Rpb4/7异构体与转化启动因子3 (eIF3) 相互作用.
- Rpb4/7对于高效的翻译启动至关重要.
- 有效的细胞质翻译需要Rpb4/7与RNA聚合酶II (Pol II) 在核中的结合.
结论:
- 这种Rpb4/7异构体作为转录和翻译之间的关键环节,表明类似于 prokaryotes 的合机制.
- RNA聚合酶II (Pol II) 可以通过Rpb4/7复合体远程控制翻译.
- Rpb4/7代表了一种新型的蛋白质类",mRNA协调者",集成mRNA生命周期阶段,用于协调基因表达.
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RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
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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
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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
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Termination of Translation
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
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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.
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