LTBP-2--STRUCTURAL AND REGULATORY FUNCTIONS

潜伏性TGF-β结合蛋白2（LTBP-2）是四种 LTBPs，并与主要的 细胞外微纤维的组成部分。 LTBP-2已在 牛系统是弹性微纤维的组成部分。 在 在人类中，LTBP-2的突变与疾病共享相关。 与马凡氏综合征相似，其特征是骨骼和 血管异常 正如其名称所示，LTBP-2也是一种TGF-β 结合蛋白，并可能调节TGF-β的活性。 在这 建议，将审查拟议的LTBP-2的双重功能。 我们 在小鼠LTBP-2基因中创建了一个靶向缺失， 它的表达。 这种突变的纯合子小鼠具有胚胎 致死表型 我们将最终研究这种致命的 表型。 首先，我们将做几个实验， 研究LTBP-2与微纤维和TGF-b的相关性， 发育和成年小鼠。 LTBP-2与弹性蛋白的关系 正常小鼠的纤维将被原位杂交研究 和免疫定位。 TGF-β与微纤维的结合将是 也检查了。 LTBP-2/TGF-b相互作用也将被抑制。 研究了 同样，原位杂交将用于确定 LTBP-2与TGF-b1、-b2和-b3时空共表达 在发育和成年小鼠中。 LTBP-2的特异性相互作用 和单个TGF-β亚型将在原发性肝癌中进行研究。 鼠组织培养物，并通过共转染在哺乳动物中表达 系统. LTBP-2上TGF-β的结合位点将使用 相同的转染系统。 在定义了LTBP-2何时何地被 与微纤维和TGF-β相关，我们将研究微纤维和TGF-β相关的基础。 LTBP-2敲除小鼠的致死表型。 性能 将在LTBP-2 -/-胚胎中检查微纤维， 这些胚胎中TGF-β的活化状态。 最后，我们将评估 LTBP-1是否可以在功能上替代LTBP-2， 老鼠.

DESCRIPTION: Latent TGF-b binding protein-2 (LTBP-2) is one of four LTBPs, and shares a high degree of identity with fibrillin, a major component of extracellular microfibrils. LTBP-2 has been shown in bovine systems to be an integral component of elastic microfibrils. In humans, mutations in LTBP-2 are associated with a disease sharing similarities with the Marfan syndrome, characterized by skeletal and vascular abnormalities. As its name indicates, LTBP-2 is also a TGF-b binding protein, and may regulate the activity of TGF-bs. In this proposal, the proposed dual function of LTBP-2 will be examined. We have created a targeted deletion in the mouse LTBP-2 gene, eliminating its expression. Mice homozygous for this mutation have an embryonic lethal phenotype. We will ultimately examine the basis for this lethal phenotype. First, we will do several experiments designed to investigate the association of LTBP-2 with microfibrils vs. TGF-b in the developing and adult mouse. The association of LTBP-2 with elastic fibers in the normal mouse will be investigated in situ hybridization and immunolocalization. Association of TGF-b with microfibrils will be examined as well. The LTBP-2/TGF-b interaction will also be investigated. Again, in situ hybridization will be used to determine the spatial and temporal coexpression of LTBP-2 with TGF-b1, -b2 and -b3 in the developing and adult mouse. The specific interaction of LTBP-2 and individual TGF-b isoforms will be investigated in primary explanted murine tissue cultures, and by co-transfection in mammalian expression systems. The binding site on LTBP-2 for TGF-bs will be determined using the same transfection systems. Having defined when and where LTBP-2 is associated with microfibrils vs. TGF-b, we will then examine the basis for the lethal phenotype of the LTBP-2 knockout mouse. Properties of microfibrils will be examined in LTBP-2 -/- embryos, as will the activation state of TGF-b in these embryos. Finally, we will assess whether LTBP-1 can functionally substitute for LTBP-2 in the developing mouse.