从核糖体的A位点开始蛋白质合成
J E Wilson1, T V Pestova, C U Hellen
1Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305, USA.
Cell
|August 31, 2000
概括
这项研究揭示了,板麻病毒的内部核糖体进入部位可以从A部位启动翻译,绕过启动器转移RNA (tRNA) 和启动因子的需要. 这一发现扩大了对核糖体如何在真核生物中启动蛋白质合成的理解.
科学领域:
- 分子生物学分子生物学
- 病毒学 病毒学
- 遗传学 遗传学 是一个
背景情况:
- 核糖体与信使RNA (mRNA) 的结合通常涉及启动转移RNA (tRNA) 与P位点的起始编码子的结合.
- 这个过程是由真核细胞启动因子2 (eIF2) 介导的,需要三酸 (GTP) 的水解.
研究的目的:
- 研究麻痺病毒在内部核糖体进入部位 (IRES) 启动翻译的机制.
- 确定是否正典翻译启动因素和启动编码识别对于IRES介导的翻译至关重要.
主要方法:
- 在病毒IRES中P位点密码体的位点定向突变发生.
- 从修改后的IRES中生成的蛋白质产品的分析.
- 生物化学测试以评估启动器tRNA,eIF2和GTP的要求.
主要成果:
- 板球麻病毒IRES形成了80S核糖体,并且在没有启动器tRNA,eIF2或GTP水解的情况下启动了翻译.
- P位码子的突变发生并没有取消翻译,这表明它没有被解码.
- 蛋白质序列分析证实,翻译是从A位点编码子 (GCU) 开始的.
结论:
- 翻译启动可以从核糖体的A位点发生,挑战传统模型.
- 病毒IRES元素可以使用替代的翻译启动机制,独立于正规宿主因素.
- 这一发现扩大了真核mRNA中翻译开放阅读框架的潜在作品集.
相关概念视频
01:31Translation
Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
02:33Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
01:31Translation
Lesson: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
01:27Ribosomes
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
02:33Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
01:29Translation in Prokaryotes
Prokaryote translation is a complex, highly coordinated process that converts genetic information from mRNA into functional proteins. It involves three stages: initiation, elongation, and termination, each facilitated by specific molecular components.Initiation of TranslationThe process begins with the assembly of the ribosomal subunits and initiation factors on the mRNA. In bacteria, the 30S ribosomal subunit recognizes the Shine-Dalgarno sequence in the mRNA, a conserved region upstream of...