STRUCTURE AND FUNCTION OF THE THROMBOSPONDIN GENE FAMILY

已知的细胞外基质蛋白不仅作为结构蛋白 组织中的元素，也影响细胞的形状，运动， 生物合成表型和增殖。在动物身上，这些功能 有助于胚胎发育、形态发生和组织 差异化。凝血酶原蛋白(TSP)属于细胞外的一类 被认为调节细胞-基质相互作用的蛋白质，并可能发挥作用 在调节细胞附着、增殖和迁移中的作用，以及在 血管生成。 这个实验室已经证明了至少有三个表达了 编码相关TSP的基因。三条蛋白质链的存在 很可能既有相似之处，也有关键的区别 结构和功能需要重新评估以前与以下方面有关的工作 TSP的位置和功能，并大大增加了潜力 TSP-细胞相互作用的复杂性以及这一功能范围 一组蛋白质可以执行。我们在这项建议中的目标是 分离并鉴定三个小鼠TSP基因，以比较其模式 在小鼠细胞和组织中的mRNA和蛋白质的表达，并评估 这些基因对生长因子和细胞因子的反应。自.以来 TSP的突变可能会产生显性的负面影响，迷你基因 将构建排除几个外显子的基因并将其导入小鼠体内。 携带这种基因的转基因小鼠可以表现出一种 反映了突变的TSP的功能。最后，有针对性地破坏 TSP基因将在体细胞中通过同源重组实现 细胞以评估TSP对细胞附着的要求， 迁徙和扩散。 预计这些实验将阐明 单独的TSP，并解决存在的可能性 杂三聚体TSP。研究一下对……的监管将是有益的。 三个基因，并将这些发现与表达模式联系起来 以及这三种蛋白质的功能。这一信息应该会增加我们的 对TSPs在组织损伤反应中作用的认识 尤其是与血管壁对内皮细胞的反应有关 损坏。

Extracellular matrix proteins are known to serve not only as structural elements in tissues but also to influence cell shape, movement, biosynthetic phenotype, and proliferation. In the animal, these functions contribute to embryonic development, morphogenesis, and tissue differentiation. Thrombospondin (TSP) belongs to a class of extracellular proteins that is thought to modulate cell-matrix interactions, and may play a role in regulating cell attachment, proliferation, and migration, and in angiogenesis. This laboratory has demonstrated that there are at least three expressed genes coding for related TSPs. The existence of three protein chains that are likely to demonstrate both similarities and crucial differences in structure and function obliges a reevaluation of previous work relating to the location and function of TSP, and greatly increases the potential complexity of TSP-cell interactions and the range of functions which this group of proteins could perform. Our objectives in this proposal are to isolate and characterize the three mouse TSP genes, to compare the pattern of mRNA and protein expression in mouse cells and tissues, and to assess the response of these genes to growth factors and to cytokines. Since mutations in TSPs are likely to exert dominant negative effects, minigenes that exclude several exons will be constructed and introduced into mice. Transgenic mice carrying such genes could demonstrate a phenotype that reflects the function of the mutated TSP. Finally, targeted disruption of the TSP genes will be performed by homologous recombination in somatic cells to evaluate the requirement of the TSPs for cell attachment, migration, and proliferation. It is expected that these experiments will clarify the function of the individual TSPs and address the possibility of the existence of heterotrimeric TSPs. It will be instructive to examine the regulation of the three genes and to relate these findings to the pattern of expression and function of the three proteins. This information should increase our understanding of the role of the TSPs in the response of tissues to injury and, in particular, to the reaction of blood vessel wall to endothelial damage.