BASEMENT MEMBRANE BIOSYNTHESIS

基底膜是一种特殊的 细胞外基质，位于上皮细胞下面，包围肌肉 细胞，并提供各种生理功能。 他们的 病理生物化学在一些疾病中也很重要， 就像衰老和发育一样。 它们的耐用性和替换性 不被理解。 我们已经表明，基底的几个主要成分 膜：前胶原IV，层粘连蛋白和巢蛋白，是密切相关的 类似于人类和果蝇， 研究果蝇基底膜形成的方法学。 我们有这些材料和其他一些材料的cDNA克隆， 已经获得了果蝇的全部核酸序列 原胶原IV。 在致命的突变体，肌球蛋白，其中肌肉 基底膜分离，我们发现这个基因编码了 一种细胞外表面受体。 我们将研究这些部分的分子功能， 基底膜成分及其受体， 在人类和果蝇中类似，例如，羧基（NC 1） IV型前胶原连接区。 我们将使用特殊的 果蝇系统重新引入基因的优势 已经被特定的定点突变改变的品系基因 在基底膜进化保守的1个部位诱变 proteins. 我们还将把这些经过修饰的基因导入 分泌基底膜的果蝇团细胞培养物 成分，分离修饰的蛋白质，并研究其 体外相互作用 我们将完成我们正在进行的 几种高分子量糖蛋白的表征 由果蝇细胞分泌， 基底膜的组成部分。 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， β链，这是几个重要的共同组成部分 细胞外基质分子的受体。 我们计划隔离 相应的果蝇受体，并表征它们。 我们已经证明了特异性抗体和核酸的实用性， 酸性探针，用于确定出现的时间和部位 基底膜IV型胶原及其mRNA在果蝇发育过程中的表达 发展 我们将使用类似的探针用于果蝇层粘连蛋白， 内陷蛋白 我们将融合基底膜的启动子区域 基因的标记β-半乳糖苷酶，研究的行动， 启动子，并将寻找共同的控制因素， 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.