REGULATION AND FUNCTION OF A HUMAN EMBRYONIC GLOBIN

人类胚胎珠蛋白的调节和功能

• 批准号: 2729732
• 负责人: J ERIC RUSSELL
• 金额: $ 21.37万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2729732
• 关键词: RNase protection assay; disease /disorder model; erythrocytes; gene expression; gene induction /repression; gene targeting; genetic regulation; genetically modified animals; hemoglobin; hemoglobin Ss; hemoprotein biosynthesis; hemoprotein structure; human genetic material tag; human tissue; laboratory mouse; messenger RNA; nuclear runoff assay; oxygen transport; polymerization; posttranscriptional RNA processing; protein structure function; pyrimidines; sickle cell anemia; sickling inhibitor; thalassemia

Human epsilon-globin is a beta-like globin whose expression is developmentally restricted to primitive erythroblasts in the blood islands of the embryonic yolk sac. In contrast to fetal and adult globins, the mechanistic bases for epsilon-globin gene regulation and the function of its encoded protein are poorly understood. Although transcriptional downregulation is a major effector of embryonic globin gene silencing, recent studies indicate that other, post-transcriptional events also play an important and previously unanticipated role in this process. Neither the specific post-transcriptional mechanisms involved, nor their ultimate contribution to epsilon-globin regulation have been established. Likewise, the physiologic properties of hemoglobins assembling from epsilon-globin subunits are incompletely described. The importance of fully defining the molecular controls and function of epsilon globin is magnified by the possibility that its reactivated expression might be therapeutically beneficial to adults with genetic defects in beta-globin expression. The feasibility and clinical potential of this approach cannot be judged without a comprehensive understanding of epsilon-globin regulation and function, which the current proposal will provide. First, key physiologically-important properties will be determined for hemoglobins that will assemble in definitive erythrocytes expressing epsilon globin. These studies, which will be done both in vitro and in transgenic mice, will include determinations of the O2 affinity and the anti-sickling characteristics of Hb alpha2epsilon2, of particular importance to individuals with beta thalassemia and sickle cell anemia. Second, the effect of specific post-transcriptional mechanisms on the expression of epsilon globin in definitive erythrocytes will be established. The specific processes that will be studied (mRNA stability, mRNA translational efficiency, and globin subunit stability, among others) are known to affect the expression of other human globins. As a group, these studies will begin to bring what is known about embryonic epsilon globin into parity with what is known about other fetal and adult globins. Moreover, the information provided by these studies will permit a reasoned approach to the design of molecular therapies aimed at epsilon-globin reactivation as well as an informed expectation of the likelihood that such an approach will be therapeutically beneficial.

人ε珠蛋白是一种β样珠蛋白，其表达在发育上仅限于胚胎卵黄囊血岛中的原始红细胞。 与胎儿和成人球蛋白相比，ε-球蛋白基因调控的机制基础及其编码蛋白的功能知之甚少。 尽管转录下调是胚胎珠蛋白基因沉默的主要效应因素，但最近的研究表明其他转录后事件也在这一过程中发挥着重要且先前未预料到的作用。所涉及的具体转录后机制及其对ε-珠蛋白调节的最终贡献都尚未确定。 同样，由ε-珠蛋白亚基组装而成的血红蛋白的生理特性也没有被完整描述。 充分定义ε珠蛋白的分子控制和功能的重要性被其重新激活的表达可能对具有β珠蛋白表达遗传缺陷的成人治疗有益的可能性所放大。 如果没有对当前提案将提供的ε珠蛋白调节和功能的全面了解，就无法判断这种方法的可行性和临床潜力。 首先，将确定血红蛋白的关键生理学重要特性，这些血红蛋白将在表达ε珠蛋白的确定红细胞中组装。 这些研究将在体外和转基因小鼠中进行，包括测定 O2 亲和力和 Hb alpha2epsilon2 的抗镰状特征，这对于患有 β 地中海贫血和镰状细胞性贫血的个体特别重要。 其次，将确定特定转录后机制对定形红细胞中ε珠蛋白表达的影响。已知将要研究的特定过程（mRNA 稳定性、mRNA 翻译效率和珠蛋白亚基稳定性等）会影响其他人类珠蛋白的表达。 作为一个整体，这些研究将开始将胚胎ε珠蛋白的已知信息与其他胎儿和成人珠蛋白的已知信息等同起来。 此外，这些研究提供的信息将允许采用合理的方法来设计旨在ε-珠蛋白再激活的分子疗法，以及对这种方法在治疗上有益的可能性的知情预期。