DIRECTIONAL TRANSPORT OF MULV GLYCOPROTEINS

我们的目标是定义膜的分子基础 糖蛋白定向运输到特定的细胞 地点。这些调查将使用病毒进行 糖蛋白被转运到不同的质膜结构域 极化的上皮细胞表面。识别分拣信号 负责糖蛋白的定向运输，我们将分析 特定修饰和序列替换对基因表达的影响 确定产生的分子的细胞位置。这些 将对病毒糖蛋白进行研究，这种蛋白表现出不同的 定位与跨膜拓扑学：人鼻咽癌gp70/p15E糖蛋白 小鼠白血病病毒，一种裂解的双功能膜糖蛋白 由疏水残基锚定的信号序列 分子的C末端，以及GPR-Gag糖蛋白，它可能 以相反的方向固定在膜上。为了 研究MuLV糖蛋白的细胞内转运途径 将使用特定的抗血清来识别参与运输的囊泡 糖蛋白从高尔基复合体到质膜的运动。 我们将确定两个MuLV编码的糖蛋白gp70/p15E和 GPR-GAG存在于相同的运输囊泡和 它们在质膜上是否相互关联。至 进一步定义与确定病毒有关的病毒成分 逆转录病毒在上皮细胞中的成熟部位，我们将进行调查 病毒在产生病毒核心的细胞中组装和释放的位置 在没有病毒糖蛋白的情况下，并确定其影响 用病毒糖蛋白补充这些细胞 顶端或基侧膜。除了提供更好的 了解基本的细胞过程，拟议的研究应该 有助于我们了解病毒感染的发病机制 通过阐明病毒成分被靶向的机制 特定的地点。

Our objective is to define the molecular basis by which membrane glycoproteins are directionally transported to specific cellular locations. These investigations will be carried out using viral glycoproteins which are transported to different plasma membrane domains on surfaces of polarized epithelial cells. To identify sorting signals responsible for the directional transport of glycoproteins, we will analyze the effects of specific modifications and sequence substitutions on determining the cellular location of the resulting molecules. These studies will be carried out with viral glycoproteins which exhibit distinct orientations and transmembrane topology: the gp70/p15E glycoprotein of murine leukemia viruses, a bitopic membrane glycoprotein with a cleaved signal sequence that is anchored by hydrophobic residues near the C-terminus of the molecule, and the gPr-gag glycoprotein which is likely to be anchored to membranes in the opposite orientation. In order to characterize the intracellular transport pathway of MuLV glycoproteins, we will use specific antisera to identify transport vesicles involved in movement of glycoproteins from the Golgi complex to the plasma membrane. We will determine whether the two MuLV-encoded glycoproteins gp70/p15E and gPr-gag are present in the same population of transport vesicles and whether they are associated with one another on the plasma membrane. To further define the viral components which are involved in determining the maturation site of retroviruses in epithelial cells, we will investigate the site of virus assembly and release in cells which produce viral cores in the absence of viral glycoproteins, and determine the effects of supplementing these cells with viral glycoproteins directed to either the apical or basolateral membranes. In addition to providing a better understanding of basic cellular processes, the proposed studies should contribute to our knowledge concerning the pathogenesis of viral infections by elucidating the mechanisms by which viral components are targeted to particular locations.