在Neurospora crassa中,重组热点通过异形序列和介质沉默控制
Patricia Jane Yeadon1, Frederick J Bowring1, David Edward Arnold Catcheside1
1College of Science and Engineering, Flinders University, Sturt Road, Bedford Park, South Australia 5042, Australia.
Genetics
|December 21, 2023
概括
在Neurospora crassa中,主要的重组抑制是由促进重组的等位基因的介质性沉默引起的. 这种机制涉及RNA-依赖RNA聚合酶,影响rec-1,rec-2和rec-3基因,揭示了一个新的调节途径.
科学领域:
- 遗传学 是一个遗传学.
- 分子生物学分子生物学
- 菌类学 菌类学是指菌类学.
背景情况:
- 几十年前确定了调节Neurospora crassa重组的基因,但它们的确切机制仍然难以捉摸.
- 在rec-1,rec-2和rec-3基因的主导等位基因抑制了特定染色体区域的重组.
- 这种主导抑制的分子基础以前并未被理解.
研究的目的:
- 阐明在Neurospora crassa.中通过rec等位基因抑制主导重组的机制.
- 调查介质沉默在调节重组中的作用.
- 描述rec-2等位基因的性质及其功能后果.
主要方法:
- 对rec-2等位基因的测序以确定序列差异.
- 引入sad-1突变 (缺乏依赖RNA的RNA聚合酶) 进入异交叉体.
- 对rec-2LG等位基因的重复诱导点 (RIP) 突变分析.
- 分析各种突变背景中的重组频率.
主要成果:
- 发现rec-2SL和rec-2LG等位基因是异形基因,在DNA序列上有显著差异.
- 这种sad-1突变减轻了对rec-2,rec-1和rec-3等位基因异构的交叉体中的重组抑制.
- 在RIP中,rec-2LG的突变产生了一个非功能性等位基因,证实了基因产品的作用.
- 通过依赖RNA的RNA聚合酶来缓解微生物沉默被确定为主导抑制的原因.
结论:
- 在Neurospora crassa中,由rec等位基因抑制重组的支配性抑制是由活性",衰退"等位基因的中介性沉默介导的.
- 这种机制阻止了活性等位基因的产物在变化过程中刺激重组.
- 在神经菌中进行重组的调节,如REC-2所示,似乎涉及一种与已知的机制不同的新途径.
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