Study of molecular pathogenesis of Fanconi anemia

范可尼贫血的分子发病机制研究

基本信息

批准号：
14570963
负责人：
YAMASHITA Takayuki
金额：
$ 2.24万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

Fanconi anemia is an autosomal recessive disorder of hematopoiesis with at least 11 genetically different groups, characterized by cellular hypersensitivity to DNA cross-linkers and chromosome instability. To date, 8 genes have been identified. A multiprotein complex including these gene products, FANCAICJE/F/G/L is required for activation of FANCD2 into a monoubiquitinated form. This active form affects genomic instability in collaboration with BRCA1 and BRCA2IFANCD1. In this project, we studied functions of FANCA mutants with amino acid substitution in its N-terminal region including nuclear localization signal and FANCG-binding sites. Our results indicate that formation of a stable complex including FANCAICIE/FIGIL is not essential for FANCD2 activation. It seems that nuclear import of FANCA/L complex palys a central role in this pathway, and that FANCG negatively regulates nuclear import of FANCA. Furthermore, we identified Hsc7O as a FANCA-binding protein. A dominant-negative form of Hsc7O and 17-AAG, a specific inhibitor of Hsp9O, inhibited nuclear localization of FANCA, suggesting that a chaperone complex including Hsc7O is required for nuclear import of FANCA. We identified FANCA mutations in 27 Japanese FA patients and found novel molecular mechanisms of generation of large deletions in this gene. We found that long-term remission of bone marrow failurewas associated with myeloid lineage-selective expansion of cells with reversion in a patient. This case suggests the clinical usefulness of gene therapy.

范可尼贫血是一种常染色体隐性造血疾病，具有至少 11 种不同的遗传基因，其特征是细胞对 DNA 交联剂过敏和染色体不稳定。迄今为止，已鉴定出8个基因。包含这些基因产物的多蛋白复合物 FANCAICJE/F/G/L 是 FANCD2 激活为单泛素化形式所必需的。这种活性形式与 BRCA1 和 BRCA2IFANCD1 协同影响基因组不稳定性。在这个项目中，我们研究了 N 端区域氨基酸取代的 FANCA 突变体的功能，包括核定位信号和 FANCG 结合位点。我们的结果表明，包括 FANCAICIE/FIGIL 在内的稳定复合物的形成对于 FANCD2 激活并不是必需的。看来FANCA/L复合物的核输入在该途径中发挥核心作用，并且FANCG负向调节FANCA的核输入。此外，我们将 Hsc7O 鉴定为 FANCA 结合蛋白。 Hsc7O 和 17-AAG（Hsp9O 的特异性抑制剂）的显性失活形式抑制 FANCA 的核定位，表明包含 Hsc7O 的伴侣复合物是 FANCA 的核输入所必需的。我们在 27 名日本 FA 患者中鉴定出了 FANCA 突变，并发现了该基因中产生大片段缺失的新分子机制。我们发现，骨髓衰竭的长期缓解与患者的骨髓谱系选择性细胞扩增和逆转有关。该病例表明基因治疗的临床用途。