模拟一个Cap-独立的翻译增强器mRNA的结构和DAP5结合点
bioRxiv : the preprint server for biology
|June 19, 2023
概括
封顶独立的翻译使用RNA结构,而不是序列,用于启动因子结合. 这一发现揭示了癌症和mRNA疗法的潜在治疗点.
科学领域:
- 分子生物学分子生物学
- 在RNA生物学,RNA生物学.
- 癌症生物学 癌症生物学
背景情况:
- 顶部独立的翻译启动允许在没有自由的5'末端的情况下进行核糖体招募,通常使用RNA结构,如病毒mRNA中的伪结.
- 细胞mRNA帽独立翻译缺乏已识别的共识RNA结构或启动因子 (eIF) 结合序列.
- 纤维细胞生长因子9 (FGF-9) mRNA使用类似IRES的独立翻译,在癌症中升级调节,与死亡相关因子5 (DAP5) 调解翻译.
研究的目的:
- 为了确定FGF-9 5' UTR.内未知的DAP5结合部位.
- 研究是否特定的RNA结构,而不是序列,调解DAP5与多种5'UTRs的结合.
- 阐明DAP5结合启动cap独立翻译的机制.
主要方法:
- 在实验室中利用SHAPE-seq来建模FGF-9 5' UTR RNA的二级和三级结构.
- 员工DAP5脚印和脚印实验,以确定DAP5的约束偏好和地点.
- 分析了RNA结构动态及其对翻译启动的影响.
主要成果:
- 模拟了FGF-9 5' UTR RNA的复杂体外结构.
- 证明了DAP5对RNA结构的一个特定面的偏好.
- 观察到DAP5结合稳定了更高能量的RNA折叠,释放了5'末端,并定位了用于核糖体招募的起始子.
结论:
- DAP5与FGF-9 5' UTR中的特定的三级RNA结构结合,而不是保留序列.
- 启动因子的结构性,而不是特定于序列的结合点可能是顶级独立翻译的一般机制.
- 这些发现为开发针对癌症的化疗药物或基于mRNA的疗法提供了新的视角.
相关概念视频
Pre-mRNA Processing: Modification of pre-mRNA Ends
9.7K
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps...
9.7K
pre-mRNA Processing
53.0K
In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
53.0K
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
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
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
Regulated mRNA Transport
6.3K
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing...
6.3K


