COMPLEMENTATION OF FA-A WITH THE DROS S3 DNA REPAIR GENE

范可尼贫血（FA）是一种复杂的常染色体隐性遗传疾病， 血液学表现的特征是进行性的， 最终致死性再生障碍性贫血，对致染色体断裂超敏 药物如丝裂霉素C（MMC），染色体断裂和显着 急性髓细胞性白血病的发病率增加。 已知有五个 FA的互补类型（A-E）。 A型是最常见的， 估计占所有患者的50 - 60%。 我们以前的 研究表明，核糖体蛋白S3是一种多功能的 具有DNA修复能力的蛋白质，其作为结合的DNA起作用 糖基化酶/AP裂解酶识别在DNA中形成的8-氧代鸟嘌呤损伤， 正常的氧化代谢。 FA-A细胞已被证明具有升高的 8-DNA中的氧鸟嘌呤水平。 使用果蝇S3 cDNA，我们有 发现S3将FA互补型A细胞补充回野生型， 型水平时，挑战与DNA损伤剂MMC。 我们提出 to：1）确定S3是否可以补充其他FA的MM灵敏度 类型和S3是否也可以补充过氧化氢（氧化 破坏剂）的FA-A细胞的敏感性，以及其他FA 2）对来自FA-A细胞的cDNA进行测序，以确定是否存在原发性 S3基因编码区存在缺陷，3）改变了S3基因的核表达， S3的定位信号，并确定这种影响对S3的能力， 补体FA-A，以及4）确定糖基化或磷酸化 S3蛋白的表达与S3蛋白的运输有关， 定位，因此，其补充FA-A的能力。 我们觉得 这些发现对于理解 FA-A DNA修复缺陷表型。

Fanconi Anemia (FA) is a complex autosomal recessive disease whose hematologic manifestations are characterized by a progressive and ultimately fatal hypoplastic anemia, hypersensitivity to clastogenic agents such as mitomycin C (MMC), chromosomal breaks and a markedly increased incidence of acute myelogenous leukemia. There are five known complementation types of FA (A-E). Type A is the most common and is estimated to account for 50-60% of all patients. Our previous investigations have shown that ribosomal protein S3 is a multifunctional protein having DNA repair capabilities acting on acting as a combined DNA glycosylase/AP lyase recognizing 8-oxoguanine lesions formed in DNA during normal oxidative metabolism. FA-A cells have been shown to have elevated 8-oxoguanine levels in their DNA. Using the Drosophila S3 cDNA, we have found that S3 complements the FA-complementation type A cells back to wild type levels when challenged with the DNA damaging agent MMC. We propose to: 1) Determine if S3 can complement the MM sensitivity of the other FA types and whether S3 can also complement the hydrogen peroxide (oxidative damaging agent) sensitivity of the FA-A cells, along with the other FA types, 2) sequence cDNAs from the FA-A cells to determine if a primary defect exists in the coding region of S3, 3) alter the nuclear localization signal of S3 and determine this effect on S3's ability to complement FA-A, and 4) determine whether glycosylation or phosphorylation of S3 is responsible for S3 trafficking and its nuclear or ribosomal localization and, therefore, its ability to complement FA-A. We feel these findings will be of significant importance in the understanding of the FA-A DNA repair defect phenotype.