wdb基因调控果蝇血细胞发育的功能及机制研究

Hematopoiesis is an important part of human and animal development. Among different species, similar and conserved regulatory mechanisms are repeatedly employed during hematopoiesis. Misregulation of hematopoiesis results in blood diseases. As known, protein phosphatase 2A (PP2A) is closely related with many types of blood diseases through regulating blood cell apoptosis. However, it remains elusive whether PP2A plays any other roles during hematopoiesis, especially the blood cell differentiation and pattern formation. PP2A functions as hetero-trimeric holoenzyme, including scaffolding subunit, regulatory subunit and catalytic subunit. Among these three subunits, regulatory subunit confers the specificity of PP2A substrate and cellular localization of PP2A holoenzyme. In the preliminary work, the applicant found that over-expressing wdb, encoding the regulatory subunit of Drosophila PP2A, dramatically inhibited the formation of crystal cell, one of three main blood cell types in Drosophila. Besides this, the applicant’s preliminary data suggested that wdb is involved to modulate Notch and Hedgehog signaling activity during Drosophila wing development. Here, we will utilize Drosophila lymph gland system, conduct genetic, molecular and developmental experiments, to study the role of wdb for different blood cell development, differentiation, and pattern formation during hematopoiesis. Furthermore, given that Notch signaling is thought to guide the formation of crystal cell and Hedgehog signaling is required to maintain the prohemocytes, the undifferentiated hemocytes, we will reveal whether this function of wdb acts through Notch or Hedgehog signaling pathway. All above, we aim to discuss the new function and new regulatory mechanism of wdb-containing PP2A during hematopoiesis, which will benefit the understanding of the relationship between protein phosphatase and blood diseases, and provide the theoretic support for the related clinic study.

血液系统发育是人及动物发育过程中的重要一环并在不同物种间表现了保守的调控机制。目前已知，蛋白磷酸酶2A（PP2A）通过调控细胞凋亡而与多种血液疾病密切相关，但其在血细胞分化及谱系形成方面的功能并不完全清楚。PP2A以三聚体形式行使功能，包括结构亚基、调节亚基和催化亚基，其中调节亚基控制PP2A的底物特异性。申请人在前期研究中发现，编码果蝇PP2A调节亚基的wdb基因抑制晶细胞（果蝇主要血细胞之一）的终端分化并在果蝇翅膀发育中调控Notch和Hedgehog信号活性。本项目拟在此基础上，利用发育生物学和分子生物学等手段，深入研究wdb基因在果蝇造血系统发育各阶段对各类血细胞形成、分化的影响，并进一步检验该基因是否通过特定信号通路调控血细胞发育，以探讨包含Wdb亚基的PP2A在造血系统发育过程中的新功能及新机制。该研究将有助于了解蛋白磷酸酶与相关血液疾病的关系，为临床研究提供理论支撑。

血液系统发育是人及动物发育过程中的重要一环并在不同物种间表现了保守的调控机制。目前已知，蛋白磷酸酶2A（PP2A）通过调控细胞凋亡而与多种血液疾病密切相关，但其在血细胞分化及谱系形成方面的功能并不完全清楚。PP2A以三聚体形式行使功能，包括结构亚基、调节亚基和催化亚基，其中调节亚基控制PP2A的底物特异性。本项目利用果蝇模式动物的造血器官淋巴腺为研究材料，聚焦于PP2A的调节亚基基因wdb，通过遗传学和发育生物学技术手段，研究wdb基因如何影响果蝇各类血细胞的分化及成熟，解析wdb在其中发挥作用的分子机制。果蝇有两类主要的终端分化的血细胞，浆细胞和晶细胞，二者在淋巴腺中由原血细胞分化而来。本项目研究结果表明Wdb蛋白在淋巴腺中广泛表达，能够通过抑制细胞增殖而负调控淋巴腺生长，而且wdb过量表达还能够抑制淋巴腺中原血细胞向浆细胞和晶细胞的分化。本项目还检测了果蝇中PP2A唯一的催化亚基基因mts在淋巴腺中的表达和功能。结果显示Mts蛋白在淋巴腺中的表达情况与Wdb蛋白类似，但是二者在对于晶细胞及其介导的黑化作用的影响并不一致，说明wdb的部分功能可能并不依赖蛋白磷酸酶复合体的组成。本项目利用果蝇模式血细胞谱系简单的优势，以针对wdb基因的研究为切入点，明确了PP2A能够调控果蝇造血器官淋巴腺的发育以及血细胞的分化成熟，初步探讨了PP2A亚基基因在造血系统发育过程中的功能及作用机制，有助于我们进一步了解蛋白磷酸酶与血液疾病发生之间的内在联系。

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