BASEMENT MEMBRANE BIOSYNTHESIS

基底膜是特殊细胞外的薄层凝结物 位于上皮细胞之下、包围肌肉细胞并提供各种服务的基质 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 人们还不了解合成和改造。 我们发现基底膜的一些主要成分是紧密相连的。 在人类和果蝇中类似，如IV型胶原和层粘连蛋白， 并确定了基底膜胶原蛋白中的一个位置 改建。我们建立了研究基底膜的方法学。 在果蝇中形成，在分化的胚胎细胞培养中 已知的蛋白质底物。在致命的突变体肌球中， 基底膜分离，我们发现这个基因编码了一种β- 整合素跨膜连接物。我们展示了它在 肌肉发生。在转基因果蝇中，我们干扰了基底膜 靶向表达反义RNA合成特定肌肉 IV型胶原。 我们将使用这样的结构来调节已知和新的合成 基底膜成分，以了解它们在序列中的作用 我们建立的基底膜的沉积。要了解 我们测序、修饰的层粘连蛋白A链结构域的功能 这些形式将在细胞培养和苍蝇中表达。我们会研究 层粘连蛋白和基底膜蛋白多糖在早期的作用 基底膜的形成阶段，以及后期两种新蛋白的形成 专业化。我们将寻找层粘连蛋白和交联剂之间的交联剂 胶原蛋白网络。 因此，分离的基底膜成分的联合研究。 区分使用和制造这些成分的细胞培养物，以及 调节这些物质在整个动物体内表达的效果， 将帮助我们了解基底膜是如何制造、修饰和 根据不断变化的需求进行重建。

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.