BASEMENT MEMBRANE BIOSYNTHESIS

基底膜是一种特殊的 位于上皮细胞下的细胞外基质，周围肌肉 细胞，并服务于各种生理功能。他们的 病理生物化学对几种疾病也很重要。 在衰老和发育过程中都是如此。其耐用性和更新换代 是不被理解的。 我们已经证明了地下室的几个主要成分 膜：IV型前胶原、层粘连蛋白和牙本质蛋白紧密相连 在人类和果蝇中相似，并建立了 果蝇基底膜形成的研究方法。 我们有这些材料和其他一些材料的cdna克隆 已经获得了果蝇的完整核酸序列 前胶原IV.在致死突变体肌球蛋白中，肌肉 基底膜分离，我们发现这个基因编码了部分 一种细胞外表面受体。 我们将研究这些部分的分子功能。 高表达的基底膜成分及其受体 类似于人和果蝇，例如，羧基(Nc1) IV型前胶原的连接结构域。我们将使用特殊的 果蝇基因再导入系统的优势 被特定的、定点的改变的品系基因 进化保守的基底膜1部分的突变 蛋白质。我们还将把这些经过修饰的基因引入到 分泌基底膜的果蝇群体细胞培养 组分，分离修饰的蛋白质，并研究它们的 体外相互作用。我们将完成正在进行的 几种高分子量糖蛋白的特性研究 是由果蝇细胞分泌的，推测是额外的 基底膜的成分。果蝇受体链 我们发现有一个非常相似的脊椎动物同源物，整合素- Beta链，它是几个重要的 细胞外基质分子的受体。我们计划分离出 相应的果蝇受体，并对它们进行表征。 我们已经证明了特定抗体和核的效用。 用于确定出现的时间和地点的酸性探针 果蝇体内基底膜IV型胶原及其mRNA的表达 发展。我们将使用类似的探针来检测果蝇层粘连蛋白和 牙菌素。我们将融合基底膜的启动子区域 基因标记的β-半乳糖苷酶，研究其作用 发起人，并将搜索共同的控制元素 基底膜蛋白及其受体。

Basement membranes are thin condensations of specialized extracellular matrix that underlie epithelia, surround muscle cells, and serve various physiological functions. Their pathobiological chemistry is important in several diseases, as well as in both aging and development. Their durability and replacement are not understood. We have shown that several major constituents of basement membranes: procollagen IV, laminin and entactin, are closely similar in man and Drosophila melanogaster, and have established methodology for studying basement membrane formation in Drosophila. We have cDNA clones for these materials and for some others and have obtained the complete nucleic acid sequence of Drosophila procollagen IV. In the lethal mutant, myospheroid, in which muscle basement membranes detach, we found that this gene codes for part of an extracellular cell surface receptor. We shall investigate the molecular functions of those parts of basement membrane components and their receptors which are highly similar in man and Drosophila, for example, the carboxyl (NC1) junctional domain of procollagen IV. We shall use the special advantages of the Drosophila system to reintroduce into the gene line genes that have been changed by specific, site-directed mutagenesis at evolutionary conserved 1 parts of basement membrane proteins. We shall also introduce these modified genes into Drosophila mass cell cultures that secrete basement membrane components, isolate the modified proteins, and study their interactions in vitro. We will complete our ongoing characterization of several high molecular weight glycoproteins that are secreted by Drosophila cells and are putative additional components of basement membranes. The Drosophila receptor chain that we found has a very similar vertebrate homolog, the integrin- beta chain, which is the common component of several important receptors for extracellular matrix molecules. We plan to isolate corresponding Drosophila receptors and characterize them. We have demonstrated the utility of specific antibodies and nucleic acid probes for defining the time and site of appearance of basement membrane collagen IV, and its mRNA, during Drosophila development. We will use similar probes for Drosophila laminin and entactin. We shall fuse the promoter regions of basement membrane genes to the marker beta-galactosidase, to study the action of the promoters, and will search for common controlling elements of basement membrane proteins and their receptors.