LYMPHOBLAST MODEL FOR DISEASES OF PURINE METABOLISM

描述：Hershfield博士实验室的长期目标 一直在定义遗传缺陷的致病生化效应 腺苷脱氨酶（ADA），负责引起 其临床后果，以发展有缺陷的治疗。的 ADA缺乏的主要后果是联合免疫缺陷， 通常在婴儿中以“严重”形式（SCID）发生，但也可能发展为 在年龄较大的儿童、青少年或成年人中，实验室的 过去对免疫缺陷发病机理的研究 重要的是开发一种有效的酶替代形式， PEG-ADA治疗。实验室参与监测治疗 患者接受PEG-ADA，因此，他们已经集中他们最近的 研究确定导致ADA缺乏症的突变。 本建议将继续这些努力，以更好地界定 特定突变与酶缺乏程度的关系 代谢和临床严重程度，对酶（和基因）的反应 替代疗法为了实现这一目标，调查人员 建议系统地研究突变对 表达ADA活性，使用E.大肠杆菌缺乏 细菌ADA基因。他们还将研究伴侣蛋白的作用， 蛋白质对突变ADA表达的影响，以鉴定 对蛋白质折叠造成潜在的可逆影响。最近， 了解到ADA缺陷（“敲除”）小鼠死于肝细胞， ADA缺乏也可导致人类肝炎 患者他们将研究基因敲除小鼠作为模型系统， 进行无法在人类患者身上进行的生化研究。

DESCRIPTION: The long-term objectives of Dr. Hershfield's laboratory have been to define the pathogenic biochemical effects of inherited deficiency of the enzyme adenosine deaminase (ADA) that are responsible for causing its clinical consequences, in order to develop defective therapy. The primary consequence of ADA deficiency is Combined Immune Deficiency, which usually occurs in a "severe" form (SCID) in infants, but may also develop insidiously in older children, adolescents, or adults. The laboratory's past research on the pathogenesis of the immune deficiency has been important to the development of an effective form of enzyme replacement therapy (PEG-ADA). The laboratory is involved in monitoring treatment of patients receiving PEG-ADA, and as a result they have focused their recent research on identifying mutations responsible for causing ADA deficiency. The present proposal will continue these efforts to better define the relationship of specific mutations to the degree of enzyme deficiency metabolic and clinical severity, in response to enzyme (and gene) replacement therapy. To further this objective the investigators have proposed to systematically investigate the effects of mutations on the expression of ADA activity, using a strain of E. coli that lacks the bacterial ADA gene. They will also investigate the effects of chaperonin proteins on mutant ADA expression in order to identify mutations that cause potentially reversible effects on protein folding. It recently been learned that ADA deficient ("knockout") mice die from liver cell degeneration, and that ADA deficiency can also cause hepatitis in human patients. They will investigate the knockout mice as a model system to carry out biochemical studies that could not be done in human patients.