Deletion of Serglycin Proteoglycan Gene in Mice

描述(由申请人提供)：该项目的长期目标是了解丝氨酸蛋白多糖的功能。这种蛋白多糖存在于妊娠期间除红系造血细胞、内皮细胞、胚胎干细胞和小鼠子宫蜕膜外的所有细胞的分泌颗粒中。丝氨酸可能的作用包括与分泌蛋白络合并包装成颗粒，调节其结构性或在细胞激活过程中的释放，以及调节其活性和递送到靶细胞。丝氨酸蛋白多糖本身可能在与细胞或细胞外基质的相互作用方面具有特定的功能。与丝氨酸相互作用的分泌蛋白包括趋化因子、细胞因子、细胞外基质蛋白和一些蛋白水解酶。因此，丝氨酸甘氨酸可能调节这些分泌蛋白介导的重要生理活动，如凝血、免疫功能、炎症、早期胚胎发育和胚胎着床。许多在体外进行的研究表明丝氨酸蛋白多糖及其糖胺多糖链在这些过程中的重要性。然而，丝氨酸在包装过程中的真正作用并最终将这些蛋白质导向其细胞靶点只能在体内确定。因此，我们建议用全局的、有条件的或细胞特异性的丝氨酸基因缺失来产生小鼠。首先，使用我们制备的靶向载体并将其电穿孔到胚胎细胞中，我们将获得胚胎干细胞克隆，这些克隆将被用来产生杂合子和纯合子血清甘氨酸缺失小鼠。其次，我们将生成一个靶向载体，该载体包含丝氨酸基因关键区两侧的loxP位点。以该载体为靶点的胚胎干细胞可以用来产生小鼠，将来可以与含有可诱导的或细胞特异性的ERE重组酶的小鼠杂交，以获得可诱导的或细胞特异性的丝氨酸基因敲除。这些动物可以用血栓或动脉粥样硬化性疾病的小鼠模型进行繁殖。这些实验最终将描述丝氨酸甘氨酸在调节正常和疾病状态下的各种关键生理功能中的作用。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand the function of the serglycin proteoglycan. This proteoglycan is contained in the secretory granules of all but erythroid hematopoietic cells, endothelial cells, embryonic stem cells, and murine uterine decidua during pregnancy. The putative roles of serglycin include complexing with and packaging secretory proteins into granules, regulating their release either constitutively or during cell activation, and modulating their activity and delivery to target cells. The serglycin proteoglycan itself may have specific functions in terms of interaction with cells or extracellular matrices. The secretory proteins which interact with serglycin include chemokines, cytokines, extracellular matrix proteins, and a number of proteases. Thus serglycin may modulate important physiologic activities mediated by these secreted proteins such as blood coagulation, immune function, inflammation, early embryonic development, and embryonic implantation. Many studies which have been performed in vitro suggest the importance of the serglycin proteoglycan and its glycosaminoglycan chains in these processes. However, the true function of serglycin in the course of packaging and ultimately directing these proteins to their cellular targets can only be determined in vivo. Therefore we are proposing to generate mice with global, conditional, or cell-specific deletion of the serglycin gene. First, using a targeting vector which we have prepared and electroporated into embryonic cells, we will obtain embryonic stem cell clones which will be used to generate heterozygous and then homozygous serglycin null mice. Second, we will generate a targeting vector containing loxP sites flanking critical regions of the serglycin gene. Embryonic stem cells targeted with this vector can be used to generate mice which can in the future be crossbred with mice containing either inducible or cell-specific ere recombinase in order to obtain inducible or cell-specific knockouts of the serglycin gene. These animals can in turn be bred with mouse models of thrombotic or atherosclerotic disease. The experiments will ultimately delineate the role of serglycin in modulating a variety of critical physiologic functions in normal and disease states.