LTBP-2--STRUCTURAL AND REGULATORY FUNCTIONS

描述：潜伏的转化生长因子-b结合蛋白-2(LTBP-2)是四种 LTBP，与纤维素有高度的同一性， 细胞外微纤维的成分。LTBP-2已显示在 牛系统是弹性微原纤维的一个组成部分。在……里面 人类，LTBP-2的突变与共同的疾病有关 与马凡综合征相似，特征是骨骼和 血管异常。顾名思义，LTBP-2也是一种转化生长因子-β 结合蛋白，并可能调节转化生长因子-β的活性。在这 根据提案，将审查LTBP-2拟议的双重功能。我们 已经在小鼠LTBP-2基因中产生了靶向缺失，消除了 它的表情。这种突变的纯合子小鼠有一个胚胎 致命的表型。我们将最终研究这一致命事件的基础 表型。首先，我们将做几个实验，旨在 研究LTBP-2与微纤维和转化生长因子-b在血管内皮细胞中的相关性 发育期和成年鼠。LTBP-2与弹性的关系 将对正常小鼠的纤维进行原位杂交研究 和免疫定位。转化生长因子-β与微原纤维的结合将是 也进行了检查。LTBP-2/TGF-b的相互作用也将是 调查过了。同样，将使用原位杂交来确定 LTBP-2与转化生长因子-β1、-β2和-β3的时空共表达 在发育中的和成年的小鼠中。LTBP-2的特异性相互作用 个别的转化生长因子-b亚型将在初步解释中进行研究 小鼠组织培养及共转染在哺乳动物中的表达 系统。在LTBP-2上与转化生长因子-b的结合部位将用 同样的转导系统。定义了LTBP-2的时间和位置 与微纤维和转化生长因子-b相关，然后我们将研究其基础 LTBP-2基因敲除小鼠的致死表型。的属性 微纤维将在LTBP-2-/-胚胎中进行检查， 转化生长因子-β在这些胚胎中的激活状态。最后，我们将评估 LTBP-1能否在功能上替代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.