BIOLOGICAL FUNCTIONS OF THROMBIN AND THROMBIN RECEPTORS

凝血酶是凝血级联反应中的关键调节酶， 在细胞活化和趋化性中起关键作用，以及 参与炎症、组织修复和神经细胞活力。 凝血酶对细胞的作用是由凝血酶受体介导的， 通过G蛋白偶联和蛋白质引起第二信使信号传导 磷酸化为了确定凝血酶的生物学功能， 凝血酶受体在体内，基因靶向将用于创建 胚胎干细胞（ES）中这些蛋白质的遗传缺陷， 小鼠这些模型将用于研究生物学作用， 凝血酶和凝血酶受体在止血和造血方面。 凝血酶原和凝血酶受体缺陷对细胞凋亡的影响 增殖和分化将直接在双 敲除ES细胞和敲除小鼠。如果小鼠缺乏凝血酶原或 凝血酶受体不能存活，将使用双敲除ES细胞 制备嵌合小鼠，以确定哪些组织可以 这些蛋白质的缺陷。免疫组织化学， 与原位RNA杂交，将用于表征 凝血酶原和凝血酶受体在正常人和正常人组织中的表达 嵌合体小鼠在发育过程中。凝血酶受体缺陷ES细胞 将研究来自缺陷小鼠的细胞系和组织， 是否可以鉴定另外的蛋白酶激活受体。这些 研究追求一种直接的方法来定义生物学功能， 凝血酶原和凝血酶受体在生长、发育和 止血。

Thrombin is a crucial regulating enzyme in the coagulation cascade and plays a critical role in cellular activation and chemotaxis, as well as being involved in inflammation, tissue repair and neural cell viability. Thrombin's effects on cells are mediated by the thrombin receptor, which evokes second messenger signaling through G-protein coupling and protein phosphorylation. To determine the biological functions of thrombin and the thrombin receptor in vivo, gene targeting will be used to create genetic deficiencies of these proteins in embryonic stem (ES) cells and mice. These models will be used to study the biological roles of thrombin and thrombin receptor in terms of hemostasis and hematopoiesis. The effects of prothrombin- and thrombin receptor-deficiencies on cell proliferation and differentiation will be studied directly in double knockout ES cells and knockout mice. If mice lacking prothrombin or the thrombin receptor are not viable, double knockout ES cells will be used to prepare chimeric mice to determine specifically which tissues can tolerate deficiencies in these proteins. Immunohistochemistry, together with in situ RNA hybridization, will be used to characterize the expressions of prothrombin and the thrombin receptor in normal or chimeric mice during development. Thrombin receptor deficient ES cell lines and tissues from deficient mice will be studied to determine whether additional protease activated receptors can be identified. These studies pursue a direct approach to define the biological functions of prothrombin and the thrombin receptor in growth, development and hemostasis.