MOLECULAR BIOLOGY OF TRANSFERRIN RECEPTOR EXPRESSION

尽管很明显转铁蛋白受体是在 部分是通过细胞内的铁，也很明显，其他调节 这其中涉及到一些机制。因为对转铁蛋白的探测 受体基因最近出现了，我们正在利用 应用分子生物学技术研究细胞周期调控 转铁蛋白受体在分子水平的表达。一个部分 这个项目的研究涉及到对小鼠浆细胞瘤基因的研究。 我们发现有两个转铁蛋白受体mRNAs。 这些细胞。有一条信息没有完整的未翻译部分- 长度的信使核糖核酸，同时保留编码序列 蛋白。 利用这个模型系统，我们计划研究铁的能力 在信息水平上调节TFR的mRNA水平。我们会 确定消息的未翻译部分是否需要 铁一般的监管。 该项目的另一部分涉及对转铁蛋白受体基因的调控。 CAMP在HL-60细胞中的转录。我们已经证明了这个阵营 在30‘-2小时内关闭c-myc和转铁蛋白受体的转录 在加法之后。我们将调查这种关闭的机制 并确定c-myc基因是否具有转录效应。 转铁蛋白受体基因。 我们已经生成了一个只包含编码的TFR结构 在LTR控制下的cDNA区。我们已经成功地 用此构建物转染3T3细胞，并证明 人转铁蛋白受体在其表面的存在 免疫沉淀和流式细胞仪分析。我们将使用这些细胞 研究病毒控制的转铁蛋白受体序列的调控。

Although it is clear that transferrin receptors are regulated in part by intracellular iron, it is also clear that other regulating mechanisms are involved. Since probes to the transferrin receptor gene have recently become available, we are utilizing molecular biology techniques to study the regulation of transferrin receptor expression at the molecular level. One part of this project involves the study of mouse plasmacytoma mRNA. We have found that there are two transferrin receptor mRNAs in these cells. One message lacks the untranslated part of the full- length mRNA, while retaining the coding sequences for the protein. Using this model system, we plan to study the ability of iron to regulate TfR mRNA levels at the level of the message. We will determine if the untranslated part of the message is necessary for iron regulation. Another part of the project involves the regulation of TfR gene transcription in HL-60 cells by cAMP. We have shown that cAMP shuts off transcription of both c-myc and TfR within 30' - 2 hours after addition. We will investigate the mechanism of this shut-off and determine if the c-myc gene has any effect of transcription of the TfR gene. We have produced a TfR construct which contains only the coding region of the cDNA under LTR control. We have successfully transfected 3T3 cells with this construct and have demonstrated the existence of human TfR on their surface by immunoprecipitation and FACS analysis. We will use these cells to study the regulation of the virally controlled TfR sequence.