非最佳的编码子使用是一种实现昼夜时钟条件的机制
Yao Xu1, Peijun Ma, Premal Shah
1Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.
Nature
|February 19, 2013
概括
菌使用非最佳的基因编码来控制昼夜节律,适应环境变化. 这种自然选择对优良的编码子进行了优化,通过调节昼夜振幅来优化适应性,挑战了关于编码子使用的先前假设.
科学领域:
- 分子生物学分子生物学
- 时间生物学 时间生物学
- 进化生物学 进化生物学
背景情况:
- 昼夜节律是生物振荡,对于适应日常环境周期至关重要.
- 在蓝藻细菌中,KaiABC蛋白质形成了核心昼夜钟振荡器.
- 最佳的编码子使用通常会提高基本基因的翻译效率,但kaiBC基因显示偏差.
研究的目的:
- 为了研究Synechococcus elongatus中昼夜节律条件的分子基础.
- 为了确定非最佳的编码子使用在调节昼夜基因表达中的作用.
- 探索对环境条件的响应中,编码子使用偏差的适应意义.
主要方法:
- 对kaiBC基因序列的实验优化,以增强KaiB和KaiC蛋白质的表达.
- 在不同温度下评估内在的昼夜节律.
- 在不同温度和昼夜节律条件下测量细胞健康状况.
主要成果:
- 优化kaiBC密码子的使用在低温下增强了内在的节奏性.
- 当昼夜节律在低温下被抑制时,细胞健康度最高.
- 自然选择有利于在较冷的环境中抑制强大的昼夜系统.
结论:
- 在kaiBC基因中,非最佳的编码子使用起到了调节昼夜节律幅度的后转录机制的作用.
- 这种基于编码子的调节允许在响应环境线索时,在昼夜和非昼夜状态之间进行适应性切换.
- 这项研究证明了自然选择对适应性表型变异和生物体适应性的最佳子的选择.
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