GENETICS OF HUMAN METAL BINDING PROTEINS

血浆中的主要铁结合蛋白转铁蛋白(Tf) 脊椎动物在铁代谢中起着至关重要的核心作用。 它是一种生长因子，需要正常和 恶性细胞。由于其对铁的高亲和力，Tf 限制了金属对微生物入侵者的可用性，以及 从而形成了其抑菌活性的重要组成部分 血浆。肝脏是转铁蛋白合成的主要部位。研究领域 我们的实验室在过去的两年里证明了 T淋巴细胞T4“诱导物”亚群合成转铁蛋白的研究 发现了一个迄今未知的转铁蛋白的自分泌作用 是淋巴细胞增殖所必需的。转铁蛋白的合成也得到了 在骨形成细胞中检测到。 转铁蛋白启动子是一种较强的真核生物 研究了推动者。影响转移率的最重要因素 合成是铁储存水平和类固醇激素。与 人转铁蛋白基因组DNA的分离与鉴定 定位与调节性相同或同源的保守序列 重金属和类固醇受体在5‘端区域的元件 Tf基因。T淋巴细胞需要的一种序列- 在Tf启动子中也发现了特异的基因表达。 区域。因此，人类转铁蛋白基因是一种很有前途的模型 基因调控的研究。 在这项拟议的研究中，分子机制涉及 将分析转铁蛋白基因的调控。自然与自然 T细胞特异性产生的62kD Tf蛋白的来源将 被刻画出来。本研究将采用的程序以 研究调节转铁蛋白生物合成的分子事件 对铁缺乏和雌激素诱导的反应包括体外 诱变、微基因导入、西南杂交和 基因组足迹。体内的转铁蛋白表达将在 转基因小鼠。 这里描述的研究结果将提供一种分子 调节细胞增殖所需基因的基础。

Transferrin (TF), the major iron-binding protein in plasma of vertebrates, plays a vital and central role in iron metabolism. It is a growth factor required for proliferating normal and malignant cells. By virtue of its high affinity for iron, TF limits the availability of the metal to microbial invaders, and thus forms an important part of the bacteriostatic activity of plasma. The liver is the major site of TF synthesis. Research in our laboratory during the past two years has demonstrated the synthesis of TF by the T4 "inducer" subset of T lymphocytes and identified a heretofore unknown autocrine role of transferrin required for lymphocyte proliferation. TF synthesis has also been detected in bone-forming cells. The TF promoter is one of the relatively strong eukaryotic promoters studied. The most important factors which influence TF synthesis are iron storage levels and steroid hormones. With the isolation and characterization of human TF genomic DNA, we have located conserved sequences identical or homologous to regulatory elements for heavy metals and steroid receptors in the 5' region of TF gene. A sequence proposed to be required for T lymphocyte- specific gene expression was also identified in the TF promoter region. The human TF gene is therefore a promising model for the study of gene regulation. In this proposed study, molecular mechanisms involved in the transferrin gene regulation will be analyzed. The nature and the origin of a 62 kD TF protein specifically produced by T cells will be characterized. The procedures to be employed in this study to investigate the molecular events that regulate TF biosynthesis in response to iron deficiency and estrogen induction include in vitro mutagenesis, minigene transfection, Southwestern blotting and genomic footprinting. TF expression in vivo will be analyzed in transgenic mice. Results from the study described here will provide a molecular basis for the regulation of a gene required for cell proliferation.