植物外显子拼接复合体（EJC）功能与进化研究

Exon junction complex (EJC) is a fundamental protein complex in eukaryotes. Its evolution and functional diversification have a close association with the eukaryotic origin. The basic biochemical function of the complex is involved in RNA metabolisms and protein translational processes. The EJC core includes MAGO, Y14, BTZ and eIF4AIII. They play an important role in the development of animals, but their functions in plants are poorly known. In particular, the functions of the BTZ and eIF4AIII in plants are not reported yet. The evolution model of each protein family and the evolutionary relationship between the four protein families throughout the eukaryotes are still unknown. Both MAGO and Y14 in Arabidopsis have a similar and broader role including pollen development and embryogenesis. Currently, we have completed preliminary evolutionary study on MAGO and Y14 gene families and characterized their functions in rice. The results give us an opportunity to assume that EJC four core members are likely subject to a process of the co-evolution and share functions in plant development. In this project, we will focus on the evolutionary analysis of the BTZ and eIF4AIII gene families, including evolutionary rate, copy number variation, gene expression differentiation in different tissues in response to various environmental stimuli and functional diversification, and discuss the underlying molecular genetic bases. Through genetically modified technologies to downregulate each gene in Physalis and rice, we will characterize their roles in plant development, especially in fertility and embryonic development. Comprehensive analysis of the evolutionary relationship of the EJC four core protein families and their functional diversifications will facilitate to understand their evolutionary significance in the evolution of plant diversity and adaptation.

外显子拼接复合体（EJC）是真核生物所特有的蛋白复合体，与真核生物的起源有密切关系。它的生化功能与RNA代谢和蛋白质翻译等有关，核心包括MAGO、Y14、BTZ和eIF4AIII。它们在动物发育起着重要作用，但在植物中的功能报道较少，其中BTZ和eIF4AIII在植物中的功能未知。核心成员的进化模式和它们之间的进化关系不清楚。我们初步完成MAGO和Y14这两个基因家族的进化和它们在水稻中的功能分析，表明EJC四个核心成员在进化过程中经历着共进化，具有广泛且相似的生物功能。在本项目中，我们将聚焦BTZ和eIF4AIII两基因家族的进化，包括进化速率、拷贝数变异、基因表达分化和功能分化样式，探讨功能分化的分子成因；通过转基因敲除分析它们及同源基因在毛酸浆和水稻发育，尤其是育性和胚胎发育中的作用；综合分析在进化过程中EJC四核心成员蛋白家族间的进化关系，探讨它们在植物多样性和适应性进化中的意义。

外显子拼接复合体（EJC）是真核生物所特有的蛋白复合体，与真核生物的起源有密切关系。它的生化功能与RNA 代谢和蛋白质翻译等有关，核心包括MAGO、Y14、BTZ和eIF4AIII。它们在动物发育起着重要作用，但在植物中的功能报道较少。这些核心成员的进化模式和它们之间的进化关系不清楚。通过本项目的执行，我们完成了这些基因家族的进化和它们在水稻和毛酸浆中的功能分析。研究表明EJC四个核心成员在进化过程中具有相同的进化历史，且经历着共进化，具有广泛且相似的生物功能，比如在营养器官和花发育中的保守功能，同时还发现它们在不同物种中的功能特化，如毛酸浆中可能参与抗病毒相关过程。进一步研究表明EJC基因可以通过影响一些基因的拼接和表达量来实现相关功能。另外，我们还发现这些基因家族重复后的功能分化，与植物的适应性进化密切相关。这些结果对于理解EJC的作用机理及其发育功能的进化具有重要的科学意义。特别的，EJC基因与植物的适应性进化及其机理值得进一步研究。