兰州大学机构库 >生命科学学院
AtRNH1C和Whirly蛋白在叶绿体DNA 修复中的功能研究
Alternative TitleAtRNH1C and Whirly are required for chloroplast DNA repair
何客彰
Thesis Advisor孙前文 ; 牟长军
2018-05-02
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name学士
KeywordR-loop 叶绿体 Whirly AtRNH1C DNA 损伤 DNA 修复
Abstract

绿色植物的光合作用是地球上有机体生存、繁殖和发展的根本源泉,而作为 光合作用的执行者—叶绿体,其基因组编码的基因高度表达,因而倾向于形成一 种由 DNA:RNA 双链及被替代出的非模板链单链形成的三链核酸结构,即 R-loop 结构。R-loop 在转录调节、DNA 复制和 DNA 修复过程中有着重大的作用,但也能 引起双链 DNA 断裂并阻碍 DNA 断裂修复,从而导致基因组的不稳定性。已知 AtRNH1C 通过抑制叶绿体基因组上 R-loop 的过量积累来维持叶绿体基因组的稳 定性。本研究对叶绿体 DNA 断裂修复不同途径中的关键因子 Whirly、AtRNH1C、 RecA1 及 PolIB 蛋白进行了系统分析,通过缺失突变体的表型鉴定及 DNA 重排分 析表明 AtRNH1C 除减少 DNA 的损伤外,在去除 DNA 断裂后形成的 RNA:DNA 结构中 也发挥重要的功能,从而保证下游 RecA1 蛋白介导的同源重组修复顺利进行。 Whirly 蛋白则通过结合单链 DNA 及自身互作的方式修复断裂的叶绿体 DNA,PolIB 蛋白作为下游因子参与到同源重组和 Whirly 介导的两条修复途径中。本研究首 次在遗传上证明了叶绿体 DNA 断裂修复因子间的关系,对叶绿体 DNA 断裂修复机 制有了更明确的认识,为植物育种及农业生产供分子水平上的借鉴。

Other Abstract

The photosynthesis of green plants is the fundamental source of the survival, reproduction and development of organisms on the earth. As the executor of photosynthesisChloroplast genome encoded genes are highly expressed, so it prone to form a kind of three strand nucleic acid structure, a DNA:RNA hybrid and the substituted non-template single strand DNA, namely R-loop structure. R-loops play important roles in transcriptional regulation, DNA replication and DNA repair, but they could also cause double-strand DNA break, leading to the genome instability. It has been known that AtRNH1C maintaining chloroplast genome stability through restricting the R-loop over- accumulation. In this study, key factors Whirly, AtRNH1C, RecA and PolIB that are involved in different pathways of chloroplast DNA repair are analyzed. Phenotyping of these loss of function mutants and DNA rearrangement analysis indicate AtRNH1C plays an essential role in removing RNA:DNA hybrids generated at DNA break sites, thus ensuring the the downstream homologous recombination repair mediated by RecA1. Whirly protein mediated chloroplast DNA repair through binding single-strand DNA and its self-interaction. PolIB acts as a downstream factor, which participates in both repair pathways that mediated by homologous recombination or Whirly. This study genetically proved the relationship between chloroplast DNA repair factors, and updated our knowledge in understanding chloroplast DNA repair mechanisms, providing reference for plant molecular breeding and agricultural production.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/222067
Collection生命科学学院
Recommended Citation
GB/T 7714
何客彰. AtRNH1C和Whirly蛋白在叶绿体DNA 修复中的功能研究[D]. 兰州. 兰州大学,2018.
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