概括
在GCN4 mRNA中的四个上游开放读取调节翻译. 突变揭示了特定的AUG编码器抑制翻译,第一个AUG在饥饿期间通过对抗抑制下游编码器来表达必不可少的AUG.
科学领域:
- 分子生物学分子生物学
- 酵母遗传学 酵母遗传学
- 基因规则 基因规则
背景情况:
- GCN4是一种酵母转录活化剂,用于氨基酸生物合成.
- 它的表达主要控制在翻译层面.
- GCN4mRNA的5'领导者含有调节元素.
研究的目的:
- 研究上游开放读取框架 (uORF) 在 GCN4 翻译调节中的作用.
- 为了确定每个uORF启动密码子对转化控制的具体贡献.
- 在饥饿条件下阐明GCN4调节的机制.
主要方法:
- 在GCN4 5'领导者uORFs内的启动子的局部定向突变发生.
- 在具有突变uORFs的酵母菌株中分析GCN4mRNA翻译效率.
- 在不同的氨基酸可用性下评估GCN4表达水平.
主要成果:
- 这四种uORF都对GCN4.4的翻译抑制至关重要.
- 两个3'近端uORF表现出比5'近端uORF更强的抑制作用.
- 第一个uORF在氨基酸饥饿期间意外地需要高效的GCN4表达,从而对抗抑制的uORFs.
结论:
- 酵母GCN4的翻译通过四个uORF的复杂相互作用来微调.
- uORFs的不同抑制作用和第一个uORF的积极调节功能对于适应性基因表达至关重要.
- 根据营养状况,GCN2和GCD1因子调节uORF相互作用.
相关概念视频
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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...
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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 addition of a...


