TRANSGENIC MODELS FOR THE STUDY OF FACTOR V FUNCTION

凝血因子V位于一个关键的调节步骤， 止血。 因子V的遗传缺陷导致严重的 先天性出血性疾病（副血友病）。 相比之下，因子V “功能获得”突变导致蛋白C抗性（因子V 莱顿（R506Q）是最常见的遗传风险因素， 血栓形成 这项建议将使用转基因小鼠模型， 探讨因子V在体内的功能及其在疾病中的作用 发病机制 在初步研究中，因子V缺陷小鼠 是通过基因打靶产生的。 令人惊讶的是， V基因敲除小鼠在早期胚胎发生过程中丢失， 出生后几小时内死于大出血 基因靶向具有 还用于将R506Q的鼠同源物插入到 内源性小鼠因子V基因。 该突变纯合小鼠 表现出严重的自发性血栓形成 具体目标是 建议将进一步检查出血和血栓形成表型 人类疾病的小鼠模型。 组织特异性转基因 表达式将被用来表征的相对贡献 不同的血浆和血小板因子V池正常止血。 的 以前未认识到的凝血成分在早期 哺乳动物的发育也将通过分析这些来探索， 其他基因工程小鼠。 最后，相对贡献 血小板和血浆因子V池与血栓形成倾向，以及 APC抵抗因子V与其他凝血因子相互作用 的组成部分，将进行调查。 这些研究应该会产生 关于因子V的生物学功能和 与APC抵抗相关的血栓形成的发病机制。 在 此外，从这些研究中产生的转基因小鼠可以提供 用于开发新型抗凝剂的强大动物模型 治疗

Coagulation factor V is located at a critical regulatory step in hemostasis. Genetic deficiency of factor V results in a severe congenital bleeding disorder (parahemophilia). In contrast, a factor V "gain of function" mutation leading to protein C resistance (factor V Leiden (R506Q) is the most common genetic risk factor for thrombosis. This proposal will use transgenic mouse models to explore the function of factor V in vivo and its role in disease pathogenesis. In preliminary studies, factor V deficient mice have been generate by gene targeting. Surprisingly, about + of the factor V null mice are lost during early embryogenesis, with the remainder dying of hemorrhage within a few hours of birth. Gene targeting has also been used to insert the murine homologue of R506Q into the endogenous mouse factor V gene. Mice homozygous for this mutation exhibit severe spontaneous thrombosis. The Specific Aims of this proposal will further examine the bleeding and thrombotic phenotypes of these murine models for human disease. Tissue-specific transgene expression will be used to characterize the relative contributions of the distinct plasma and platelet factor V pools to normal hemostasis. The previously unrecognized role of coagulation components in early mammalian development will also be explored by analysis of these and other genetically engineered mice. Finally, the relative contributions of platelet and plasma factor V pools to thrombophilia, as well as the interaction between APC resistant factor V and other coagulation components, will be investigated. These studies should yield valuable new information concerning the biologic functions of factor V and the pathogenesis of thrombosis associated with APC resistance. In addition, the transgenic mice generated from these studies may provide powerful animal models for the development of novel anticoagulant therapies.