Genetic Analysis of Iron Homeostasis in Zebrafish

描述（由申请人提供） 维持铁稳态对正常造血和造血干细胞的生长至关重要。 预防因铁过载而导致的器官损伤。虽然C282Y突变在 HFE基因在高加索人群中很常见， 遗传性血色素沉着症是相当可变的（1），表明其他基因， 也参与铁稳态的调节。斑马鱼Danio rerio，提供了一个很好的遗传系统，用于鉴定新的 铁代谢相关的基因，如最近鉴定的 通过突变的定位克隆新的铁转运蛋白ferroportin1 导致低色素斑马鱼突变体weissherbst（2）。分析 在大规模化学诱变筛选中产生的突变体，我有 发现了另一种低色素性贫血突变体HF107，它映射到一种新的 位于斑马鱼20号染色体上。我建议克隆一个基因 这个突变体和表征基因产物。互补研究和 另一个低色素性贫血突变体HM 007的低分辨率图谱， 结果鉴定出一种新的Weissherbst等位基因， 比之前鉴定的等位基因贫血程度轻。确定 这种新等位基因的遗传基础可以提供对调控的深入了解， ferroportin1的功能。此外，我建议将ferroportin1放置在 通过对斑马鱼进行筛选控制铁稳态的遗传途径 克服铁转运蛋白1功能缺陷的突变。我们假设 ferroportin1在维持铁稳态中起着关键作用， 其调节和功能依赖于特定基因，这些基因可能 在抑制器屏幕中识别。这些可能包括（1）hephaestin（2）HFE (3)转铁蛋白受体（4）新基因，包括假定的铁储存 （5）替代性铁转运蛋白。在 此外，我们希望在ferroportin1基因中发现功能获得突变 本身进行诱变筛选有助于评价突变的可能性。 所有这些因素同时相互作用，可能导致 鉴定参与铁稳态的新基因。这些新基因 可能成为治疗铁过载病症的分子靶点， 例如遗传性血色病。

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.