MEMBRANE GLYCOPROTEIN CHANGES DURING DIFFERENTIATION

已有证据表明雌激素诱导的小鸡输卵管 膜糖蛋白是转铁蛋白受体。雌激素 治疗诱导输卵管分化，包括 蛋清蛋白的生物合成。一种蛋清蛋白， 卵白蛋白(卵转铁蛋白)，作为铁的来源 发育中的胚胎。为了获得大量的铁 输卵管转铁蛋白受体是分泌卵白蛋白所必需的 也是由雌激素诱导的。抗体和/或特异性 寡核苷酸探针(基于N端序列分析)将 用于从Lambda中获得转铁蛋白受体cDNA. Gtll表达文库。该cdna将用于获得蛋白质。 序列，并测量稳定状态的mRNA水平，转录 受体信使核糖核酸活性及其半衰期。种族隔离 转铁蛋白受体(卵白蛋白)在 从其合成的现场(S)移动到细胞表面 使用转铁蛋白受体抗体，刀白蛋白进行研究 抗体和免疫电子显微镜金标或铁蛋白- 偶联二抗。此外，还将尝试 为获得假定的转铁蛋白受体特异性囊泡而制作的 蔗糖梯度离心法。取决于结果 分离研究可能会进行额外的实验 以确定转铁蛋白受体何时获得其结合 能力，以及这可能如何影响囊泡分离。

Evidence has been obtained that an estrogen=induced chick oviduct membrane glycoprotein is the transferrin receptor. Estrogen treatment elicits oviduct differentiation which includes the biosynthesis of egg white proteins. One of the egg white proteins, conalbumin (ovotransferrin), serves as an iron source for the developing embryo. In order to obtain the large amounts of iron necessary for conalbumin secretion the oviduct transferrin receptor is also estrogen-induced. Antibodies and/or a specific oligonucleotide probe (based on N-terminal sequence analysis) will be employed to obtain a transferrin receptor cDNA from a lambda gtll expression library. The cDNA will be used to obtain protein sequence and to measure steady-state mRNA levels, transcriptional activity of receptor mRNA and mRNA half-life. The segregation of transferrin receptor from conalbumin (ovotransferrin) during movement from their-site(s) of synthesis to the cell surface will be studied using transferrin receptor antibodies, conalbumin antibodies and immunoelectron microscopy with gold- or ferritin- conjugated secondary antibodies. Additionally, an attempt will be made to obtain the putative transferrin receptor-specific vesicles by sucrose gradient centrifugation. Depending on the outcome of the segregation studies additional experiments may be undertaken to determine when the transferrin receptor acquires its binding capability and how that might affect vesicular segregation.