MECHANISMS FOR DETERMINATION AND DIFFERENTIATION OF CHONDROCYTES

这一应用是基于特定转录的假设 因素在形成特定部分的过程中起着至关重要的作用 哺乳动物骨骼和在测定和分化 胚胎发育中的软骨细胞。此应用程序被细分为 分为两个不同的部分。我们最近确定了一部小说的DNA 含有同源结构域的蛋白Cart1，它选择性地在 特异间充质细胞，位于前软骨细胞和软骨细胞中。这个 本提案的第一部分是研究完整的Cart1的功能 通过对小鼠和胚胎进行广泛的表型表征 并在转基因小鼠中研究Cart1基因 控制Cart1基因表达的转录机制 在前软骨细胞和软骨细胞中。CART-1缺陷小鼠表现出 类似于人类失能综合征的表型。 此应用程序的第二部分基于以下假设 软骨细胞特异性转录因子(S)控制软骨细胞的激活 终末期的典型标志物前α1(II)胶原基因 成熟软骨细胞的分化。我们建议定义最小 COL2A1基因内含子1的序列赋予软骨细胞- β-半乳糖苷酶报告基因在转基因中的限制性表达 小鼠和胚胎，以表征结合软骨细胞的特异性蛋白 到这个最小的功能活性序列，并克隆它们的cDNA。 这项申请建议研究发挥作用的转录因子 在骨骼形成的两个不同方面发挥关键作用。

This application is based on the hypothesis that specific transcription factors play a critical role in the formation of specific parts of the mammalian skeleton and in the determination and differentiation of chondrocytes during embryonic development. This application is subdivided in two different parts. We have recently identified the DNA for a novel homeodomain containing protein, Cart1, which is selectively expressed in specific mesenchymal cells, in prechondrocytes and chondrocytes. The first part of this proposal is to examine the function of Cart1 in intact mice and embryos by an extensive characterization of the phenotype of mice that are deficient in Cart1 and to study in transgenic mice the transcriptional mechanisms which control the expression of the Cart1 gene in prechondrocytes and chondrocytes. Cart-1 deficient mice show a phenotype that is similar to a human acrania syndrome. The second part of this application is based on the hypothesis that other chondrocyte-specific transcription factors(s) control the activation of the gene for proalpha1(II) collagen, a typical marker of terminal differentiation of mature chondrocytes. We propose to define the minimal sequence in intron 1 of the COL2A1 gene which confers chondrocyte- restricted expression to a beta-galactosidase reporter gene in transgenic mice and embryos, to characterize chondrocyte-specific proteins which bind to this minimal functionally active sequence and to clone their cDNAs. This application proposes to study transcription factors that play a critical role in two different aspects of skeletogenesis.