通过新生的翻译核糖体的指令
1Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Science (New York, N.Y.)
|September 14, 2002
概括
大肠杆菌中的酸酶操作子使用领导 (TnaC) 和酸来调节基因表达. 在TnaC合成过程中,托芬与核糖体结合,触发了这种诱导过程.
科学领域:
- 分子生物学分子生物学
- 微生物遗传学 微生物遗传学
- 基因规则 基因规则
背景情况:
- 埃舍里希亚大肠杆菌的托酶操作子表达受到代体抑制和托诱导的转录反终止的控制.
- 氨酸诱导涉及领导 (TnaC) 和翻译核糖体内的特定位置.
研究的目的:
- 为了阐明E.大肠杆菌型酶操作中型诱导的转录反终结的精确机制.
- 为了确定在TnaC合成过程中感知托所涉及的特定部位和分子相互作用.
主要方法:
- tnaC基因的位点定向突变发生,包括取代停止编码子.
- 使用记者基因试验分析托诱导的抗终结反应.
- 研究TnaC中特定氨基酸残留的作用,特别是-12的作用.
主要成果:
- 将tnaC停止编码子替换为托编码子,使得托充电的tRNA可以起到诱导作用.
- 被充电tRNA的三甲基占据的核糖体A位点被确定为诱导位点.
- 在出道中的新生TnaC中,-12的位置对于诱导至关重要.
结论:
- 在核糖体内新生的序列可以直接影响翻译的延续和终止.
- 这项研究揭示了一种在转化水平上调节基因的新机制,这种调节是由特定的氨基酸结合和核糖体相互作用介导的.
- 这提供了更深入的了解细菌如何感知和响应环境信号,如托.
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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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