MEMBRANE GLYCOPROTEIN CHANGES DURING DIFFERENTIATION

有证据表明，雌激素诱导的鸡输卵管 膜糖蛋白是转铁蛋白受体。 雌激素 治疗输卵管分化，包括 卵白色蛋白的生物合成。 其中一种卵白色蛋白， 伴清蛋白（卵转铁蛋白），作为铁源， 胚胎发育 为了获得大量的铁 伴清蛋白分泌所必需的输卵管转铁蛋白受体 也是雌激素诱导的 抗体和/或特异性 寡核苷酸探针（基于N末端序列分析）将 用于从λ细胞获得转铁蛋白受体cDNA， gtll表达式库。 cDNA将用于获得蛋白质 序列和测量稳态mRNA水平，转录 受体mRNA活性和mRNA半衰期。 的偏析 伴清蛋白转铁蛋白受体（卵转铁蛋白） 从它们的合成位点到细胞表面的运动将 使用转铁蛋白受体抗体、伴白蛋白 抗体和免疫电镜与金-或铁蛋白- 偶联二抗。 此外，还将尝试 以获得推定的转铁蛋白受体特异性囊泡 通过蔗糖梯度离心。 取决于 分离研究可以进行额外的实验 以确定转铁蛋白受体何时获得结合 能力以及如何影响囊泡分离。

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.