植物过氧化物酶体发生的分子机理研究

Peroxisomes are small and single-membrane bound eukaryotic organelles. Their multiplicity of functions is essential on many aspects of plant development and survival. Significant process has been made in recent ten years in the mechanism of peroxisome formation, including sorting of membrane and matrix proteins and recently the turnover of this organelle. The molecular mechanism of the biogenesis process is still unclear in many aspects, e.g. assembly process of peroxisomes, source of the membrane structure, how peroxisomal membrane proteins (PMPs) are targeted to the membrane, what’s the nature of the preperoxisome, and the organization of the membrane proteins on peroxisomes. In recent work, we found that DAYU as a peroxisomal membrane protein essential for peroxisome biogenesis is involved in pollen germination on the stigma. We also found that PEX13 another PMP working together with DAYU by direct interaction functions in pollen germination. The goal of this proposal is to study the molecular mechanism of peroxisome biogenesis through the classic and newly developed microscopic techniques based on the research of DAYU. First, we will study the dynamic assembly of DAYU-GFP and the mutation DAYUC267-GFP from the ER to the mature peroxisome by spin disk laser scanning microscopy and super-resolution fluorescence microscopy. And further, by these approaches, we will analyze the fusion processes of the preperoxisomes and the association between peroxisomes and other organelles. Second, using tag affinity purification and proteomic LC-MS/MS analysis, we will isolate the interacting proteins of DAYU and other PMP proteins. Third, by interaction mapping and topology dissection, we will construct the interaction network between PMPs and proteins on other associating organelles. Fourth, using loss-of-function approaches, we will evaluate the function of the known and new PMPs in pollen germination and peroxisome biogenesis. Our studies will improve the understanding of the molecular mechanism of plant peroxisome biogenesis and possible clues on regulatory mechanism of peroxisome plasticity and association with other organelles.

过氧化物酶体是真核细胞中一类重要的细胞器。在高等植物中，过氧化物酶体在生长发育、生物和非生物胁迫等多方面发挥着重要作用。目前，人们对过氧化物酶体发生过程的分子机制有了初步了解，但是如过氧化物酶体的来源，过氧化物酶体发生的动态过程，膜蛋白的组装，膜蛋白跨膜整合，膜蛋白如何发挥功能，过氧化物酶体和其他细胞器的关系等问题的分子机理了解有限。我们发现，过氧化物酶体膜蛋白DAYU和PEX13相互作用，调控过氧化物酶体的发生，参与花粉的萌发。本研究将在前期基础上，阐明过氧化物酶体的发生的分子机制，探索其与其它细胞器之间的关系。该研究将增进人们对过氧化物酶体发生这一基本细胞生物学问题的认识，对农业经济具有理论指导意义。

过氧化物酶体是真核细胞中一类由单层膜包裹的细胞器。在高等植物中，过氧化物酶体在生长发育、生物和非生物胁迫等多方面发挥着重要作用。目前，人们对植物细胞中过氧化物酶体发生过程的分子机制有了初步了解，但对过氧化物酶体的来源，过氧化物酶体发生的动态过程，膜蛋白的运输和跨膜整合，过氧化物酶体和其他细胞器的关系等问题的分子机理了解有限。通过本项目四年的研究，我们发现，在植物细胞中，ER对过氧化物酶体发生有着重要的功能，同时，叶绿体同样对过氧化物酶体的成熟至关重要。其次，我们筛选了多个可能参与过氧化物酶体发生的相关因子，并对几个关键的调节因子进行初步的定位、互作及功能分析，确定它们参与调控了过氧化物酶体发生。最后，我们在拟南芥花粉中建立一个研究植物细胞过氧化物酶体生物发生的研究体系，为下一步更深入研究提供了技术平台和保障。综上，本研究按计划取得了预期的进展和成果，这些研究结果将增进人们对过氧化物酶体发生这一基本细胞生物学问题的认识。并为研究组后续在该领域的深入研究奠定了重要基础。