概括
卵泡蛋白信使RNA (mRNA) 上的多A尾部对于无细胞系统中高效的蛋白质翻译至关重要. 删除这种尾巴会降低翻译效率,特别是影响蛋白质合成的重新启动.
科学领域:
- 分子生物学分子生物学
- 基因表达 基因表达
- 蛋白质合成 蛋白质合成
背景情况:
- 众所周知,在真核信使RNA (mRNA) 的3'端的多元A序列在mRNA稳定性和翻译中起作用.
- 聚甲尾对转化效率的具体贡献,特别是关于重新启动,需要进一步研究.
研究的目的:
- 为了研究多元A序列对卵蛋白mRNA转化效率的影响.
- 要确定多A) 移除是否影响mRNA稳定性或翻译启动/重新启动.
主要方法:
- 使用多核酸酶从卵泡蛋白mRNA中选择性去除多核酸尾.
- 在无细胞网细胞溶解体系统中评估mRNA稳定性.
- 对多体体大小,延长率和每个mRNA的翻译回合的分析,无论是网细胞溶解物还是无小麦胚芽细胞系统.
主要成果:
- 在无细胞系统中,多A去除没有显著影响mRNA稳定性.
- 死亡化卵蛋白mRNA在网细胞溶解体系统中表现出较低的翻译效率.
- 这种减少归因于重新启动的效率下降,正如多体分析和翻译回合所证明的那样.
- 在小麦芽系统中没有观察到类似的差异,该系统支持更少的翻译轮.
结论:
- 在网细胞溶解体系统中,聚甲尾对于有效地重新启动卵蛋白mRNA的翻译至关重要.
- 在允许多轮翻译的系统中,在翻译效率方面,多个 (A) 尾的作用更加明显.
- 这些发现凸显了3'多A序列在转录后调节基因表达中的功能重要性.
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
02:07Improving Translational Accuracy
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
01:44Termination 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...
02:28Leaky Scanning
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
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
01:29Translation 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...