Genetic Analysis of Iron Homeostasis in Zebrafish

描述(由申请人提供) 维持铁的动态平衡对于正常的造血和 预防因铁负荷过多造成的器官损伤。虽然C282Y突变在 HFE基因在高加索人群中常见，其外显率为 遗传性血色素沉着症有很大的变异性(1)，这表明其他基因 也参与铁的动态平衡调节。斑马鱼，达尼奥 Rerio，为小说的鉴定提供了一个很好的遗传系统 参与铁代谢的基因，最近发现的 通过突变定位克隆新的铁转运蛋白铁蛋白1 对低色斑马鱼突变体Weissherbst负责(2)。分析 在大规模化学诱变筛选中产生的突变体，我已经 发现了另一个患有低色素性贫血的突变体HF107，该突变体映射到一种新的 斑马鱼20号染色体上的基因。我建议克隆与 并对该基因产物进行鉴定。互补性研究和 另一株低色素性贫血突变体HM007的低分辨率定位 导致了Weissherst的一个新等位基因的鉴定，似乎 他们的贫血程度没有之前发现的等位基因严重。确定 这种新等位基因的遗传学基础可能为我们提供对调控和 铁蛋白1的功能。此外，我建议将铁门蛋白1放在一个 通过对斑马鱼进行筛选来控制铁稳态的遗传途径 克服铁蛋白1功能缺陷的突变。我们假设 铁蛋白1在维持铁稳态方面起着关键作用，而且 它的调节和功能依赖于特定的基因，这些基因很可能是 在抑制器屏幕中标识。这些药物可能包括(1)Hephestn(2)HFE (3)转铁蛋白受体(4)新基因，包括假定的铁储存 调节剂和红细胞生成调节剂(5)替代铁转运体。在……里面 此外，我们希望在铁蛋白1基因中发现功能突变的收益 它本身。进行诱变筛查有助于评估 所有这些因素同时相互作用，并可能导致 铁稳态相关新基因的鉴定。这些新基因 可能成为治疗铁超载状况的分子靶点， 例如遗传性血色素沉着症。

DESCRIPTION (provided by applicant) Maintaining iron homeostasis is essential for normal hematopoiesis and the prevention of organ damage due to iron overload. Although the C282Y mutation in the HFE gene is commonly found in the Caucasian population, the penetrance of hereditary hemochromatosis is quite variable (1), suggesting that other genes also participate in the regulation of iron homeostasis. The zebrafish, Danio rerio, provides an excellent genetic system for the identification of novel genes involved in iron metabolism, as evidenced by the recent identification of the novel iron transporter ferroportin1 by positional cloning of the mutation responsible for the hypochromic zebrafish mutant, weissherbst (2). Analyzing mutants generated in a large scale chemical mutagenesis screen, I have identified another mutant with hypochromic anemia, HF107, that maps to a novel locus on zebrafish chromosome 20. I propose to clone the gene responsible for this mutant and to characterize the gene product. Complementation studies and low-resolution mapping of another mutant with hypochromic anemia, HM007, resulted in the identification of a new allele of weissherbst that appears to have less severe anemia than the previously identified alleles. Determining the genetic basis for this new allele may provide insight into the regulation and function of ferroportin1. Furthermore, I propose to place ferroportin1 in a genetic pathway governing iron homeostasis by performing a screen for zebrafish mutations that overcome a defect in ferroportin1 function. We hypothesize that ferroportin1 plays a critical role in maintaining iron homeostasis and that its regulation and function depend on specific genes which are likely to be identified in the suppressor screen. These may include (1) hephaestin (2) HFE (3) transferrin receptor (4) novel genes including the postulated iron stores regulator and erythropoietic regulator (5) alternative iron transporters. In addition we expect to find gain of function mutations in the ferroportin1 gene itself. Performing a mutagenesis screen facilitates evaluation of the interactions of all these factors simultaneously and may result in the identification of novel genes involved in iron homeostasis. These novel genes may become molecular targets for the treatment of iron overload conditions, such as hereditary hemochromatosis.