BASEMENT MEMBRANE BIOSYNTHESIS

基底膜是细胞外特化细胞的薄凝聚物， 上皮细胞下面的基质，包围肌肉细胞，并为各种 生理功能。 它们的病理生物化学很重要 在几种疾病中，以及在衰老和发育中。 他们的 合成和重塑还不清楚。 我们发现，基底膜的一些主要成分是密切相关的， 在人和黑腹果蝇中类似，例如胶原IV和层粘连蛋白， 并确定了基底膜胶原蛋白中的一个位点， 重塑 我们建立了研究基底膜的方法学 在果蝇中形成，在胚胎细胞培养物中分化， 已知的蛋白质底物。 在致命的突变型肌球蛋白中， 基底膜分离，我们发现这个基因编码一个β- 整合素跨膜连接子。 我们展示了它在以下方面的关键作用： 肌生成 在转基因果蝇中， 通过靶向表达反义RNA合成特异性肌肉， 胶原蛋白IV。 我们将使用这样的结构来调节已知的和新的 基底膜成分，以了解其在序列中的作用 我们建立的基底膜沉积。 学习 层粘连蛋白A链结构域的功能， 形式将在细胞培养物和果蝇中表达。 我们会研究 层粘连蛋白和基底膜蛋白多糖在早期 基底膜形成的阶段，和两个新的蛋白质在后期 专业化 我们将寻找层粘连蛋白和 胶原蛋白网络。 因此，联合研究分离的基底膜成分， 分化细胞培养，使用和制造组件，以及 调节这些物质在整个动物中的表达的效果， 将帮助我们了解基底膜是如何形成、改变和 根据不断变化的需求进行改造。

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 synthesis and remodelling are not understood. We showed that some major constituents of basement membranes are closely similar in man and Drosophila melanogaster, e.g. collagen IV and laminin, and identified a site in basement membrane collagen that is cut during remodelling. We established methodology for studying basement membrane formation in Drosophila, and in embryo cell cultures differentiating on known protein substrates. In the lethal mutant myospheroid, in which basement membranes detach, we found that this gene codes for a beta- integrin transmembrane connector. We demonstrated its pivotal role in myogenesis. In transgenic flies we interfered in the basement membrane synthesis of specific muscles by targeted expression of antisense RNA to collagen IV. We shall use such constructs to modulate the synthesis of known and new basement membrane components, to learn their role in the sequential deposition of basement membranes that we established. To learn the functions of domains of the laminin A chain that we sequenced, modified forms will be expressed in cell cultures and flies. We will study the roles of laminin and of basement membrane proteoglycan in the early stages of basement membrane formation, and of two new proteins in later specialization. We shall look for a crosslinker between laminin and collagen networks. Thus the combined study of isolated basement membrane components of differentiating cell cultures that use and make the components, and of the effects of modulating expression of these materials in whole animals, will help us to learn how basement membranes are made, modified, and rebuilt according to changing needs.