植物微丝解聚因子ADF在进化过程中功能发生分化的分子机制研究

发布时间：2018-01-18 15:43

本文关键词：植物微丝解聚因子ADF在进化过程中功能发生分化的分子机制研究　出处：《兰州大学》2017年博士论文　论文类型：学位论文

【摘要】：同源基因功能的分化为生物进化提供了遗传材料和动力。在生物体中,基因发生复制后,子基因在自然选择压力下会经历假基因化,亚功能化和新功能化三种不同的功能分化命运,然而由于分子进化的驱动模式和过程难于重建,子基因功能分化命运模型依然存在争议,因此研究基因家族的功能分化对于揭示生物分子进化过程有重要意义。微丝解聚因子(Actin-depolymerizing factors,ADFs)是一类重要的微丝结合蛋白,在真核生物中广泛存在。ADFs具有保守的剪切和解聚微丝的功能,并参与生物细胞中微丝骨架的动态调节。在植物中,actin和ADFs发生了共进化,在此过程中ADF家族基因的数目增多,并且生化功能发生了分化。然而,植物ADFs的生化功能和进化过程中的功能分化的分子机制依然未知。本文对模式植物拟南芥ADF基因家族的所有11个成员的生化功能进行了研究,并取得了以下研究结果:(1)揭示了拟南芥ADF基因家族的生化功能发生了分化,并形成两种类型,即成束型功能(B-type)和解聚型功能(D-type)。(2)研究发现属于第三亚家族的AtADF5和AtADF9从保守的微丝剪切和解聚功能进化成了微丝成束功能,并且成束微丝的能力受pH调控。(3)研究表明第一亚家族AtADF1、AtADF2、AtADF3和AtADF 4剪切和解聚微丝的能力有所增强。(4)通过对该家族祖先基因的重建和生化功能的分析,发现一些关键氨基酸残基的突变对拟南芥和其他物种的ADFs生化功能有重要影响。揭示了ADFs生化功能的分化在被子植物进化中是相对保守的。(5)研究发现植物ADFs第三亚家族成员N端氨基酸序列由于内含子滑动出现延伸,说明该过程对于ADFs解聚型功能和成束型功能的分化是必不可少的。综上所述,植物ADFs基因家族的生化功能从一种典型的解聚型功能分化出了另一种成束型功能,并且ADFs氨基酸序列N端的延长和一些保守功能位点的形成对该家族基因功能的分化具有重要意义。
[Abstract]:The functional differentiation of homologous genes provides genetic materials and power for biological evolution. In organisms, after gene replication, subgenes undergo pseudogenization under the pressure of natural selection. Subfunctionalization and neo-functionalization have three different fates of functional differentiation. However, the fate model of subgene functional differentiation is still controversial because the driving mode and process of molecular evolution are difficult to reconstruct. Therefore, it is important to study the functional differentiation of gene family in order to reveal the evolution process of biomolecules. Microfilament depolymerizing factors. ADFs are a kind of important microfilament-binding proteins. ADFs have the functions of conserved shear and depolymerization of microfilaments in eukaryotes. And involved in the dynamic regulation of microfilament cytoskeleton in biological cells. In plants, actin and ADFs coevolved, and the number of ADF family genes increased in the process. And the biochemical function has been differentiated. The biochemical function of plant ADFs and the molecular mechanism of functional differentiation during evolution are still unknown. The biochemical functions of all 11 members of ADF gene family of Arabidopsis thaliana were studied in this paper. The following results: 1) revealed that the biochemical function of Arabidopsis ADF gene family differentiated and formed two types. Beam-forming function B type) and depolymerization function D type 2). It was found that AtADF5 and AtADF9, which belong to the third sub-family, evolved from conserved microfilament shearing and depolymerization to microfilament bundles. The ability of strands of microfilaments was regulated by pH.) the first subfamily, AtADF1 and AtADF2, were studied. The ability of AtADF3 and AtADF 4 to cut and depolymerize microfilaments was enhanced. Some mutations of key amino acid residues were found to have an important effect on the ADFs biochemical function of Arabidopsis thaliana and other species, which revealed that the differentiation of ADFs biochemical function was relatively conserved in angiosperm evolution. It was found that N-terminal amino acid sequences of plant ADFs family members extended due to intron slippage. It shows that this process is essential for the differentiation of ADFs depolymerization function and bunching function. The biochemical function of plant ADFs gene family is differentiated from one typical depolymerization function and another bunchy function. The prolongation of N-terminal of ADFs amino acid sequence and the formation of some conserved functional sites play an important role in the functional differentiation of the family.
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q943.2

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