由uORFs进行翻译性调节和启动密码区选择严格性
Thomas E Dever1, Ivaylo P Ivanov1, Alan G Hinnebusch1
1Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA thomas.dever@nih.gov ivaylo.ivanov@nih.gov ahinnebusch@nih.gov.
Genes & development
|July 11, 2023
概括
上游开放阅读框架 (uORF) 通过控制主开放阅读框架 (mORF) 的翻译来调节基因表达. 本综述探讨了uORFs如何抑制或刺激翻译,重点关注核糖体队列和延迟重新启动模型的替代方案.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 基因规则 基因规则
背景情况:
- 细胞信使RNAs (mRNAs) 通常包含上游开放的读取 (uORFs),先于主要蛋白质编码序列 (mORF).
- 虽然uORFs通常具有抑制作用,但在调节mORF的翻译效率方面起着至关重要的作用.
- 了解uORF功能是解读复杂基因表达控制的关键.
研究的目的:
- 审查uORFs调节mRNA翻译的多种机制.
- 要突出核糖体队列在uORF介导的转化抑制中的作用.
- 批判性地评估uORF监管的新兴模型,将它们与已建立的理论 (如延迟重新启动) 相比较.
主要方法:
- 文献综述和现有关于uORF功能研究的综合.
- 分析支持不同监管模式的实验证据.
- 对uORF介导的翻译控制提出的机制进行比较评估.
主要成果:
- uORFs具有双重作用,能够同时抑制和刺激mORF转换.
- 核糖体排队是一个重要的机制,有助于uORFs的翻译抑制.
- 最近的发现挑战了对uORF调节的延迟重新启动模型的普遍性,特别是对于GCN4/ATF4mRNAs.
结论:
- uORFs是基因表达的多功能调节者,具有上下文依赖的效果.
- 核糖体队列为uORF介导的抑制提供了一种机理性的解释.
- 需要进一步的研究,以充分阐明uORF监管的替代模式及其影响.
相关概念视频
Leaky Scanning
5.2K
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...
5.2K
Translational Regulation
45
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
45
Improving Translational Accuracy
11.6K
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...
11.6K
Initiation of Translation
34.2K
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...
34.2K
Regulation of Expression at Multiple Steps
945
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the...
945
Transcriptional Regulation: Riboswitches
61
Riboswitches are RNA elements that regulate gene expression by altering their secondary structures in response to specific effector molecules. These elements, located in the leader regions of certain mRNAs, act as transcriptional regulators by toggling between alternative conformations to control downstream gene expression. Riboswitch-mediated regulation is a precise mechanism for modulating biosynthetic pathways, as exemplified by the riboflavin biosynthesis pathway in Bacillus...
61


