ROLE OF BHLH PROTEIN SCL IN HEMATOPOIETIC DEVELOPMENT

红细胞发育所需的核调节蛋白不是 完全定义。在其他发育系统中，基本蛋白质 螺旋-环-螺旋 (bHLH) 家族通常参与细胞命运的确定。 bHLH 因子称为 SCL（干细胞白血病）（也称为 tal- 1/TCL5) 是在红系细胞中发挥重要作用的潜在候选者 发展。在这个项目中，小鼠 SCL 基因将被灭活 胚胎干细胞和纯合缺陷小鼠的基因靶向 将生成 SCL。这些小鼠的表型将是 其特征贯穿胚胎发生和成体生命（如果可行）。在 此外，SCL 缺陷纯合的 ES 细胞将从 单个敲除细胞以评估造血和红细胞 体外发育。如果体外或体内的表型不 在缺乏 SCL 的情况下，系统性地寻找潜在的 将进行多余的蛋白质，并涉及 SCL 的杂交育种 具有其他 bHLH 敲除的杂合子（例如 Lyl）。为了进一步 研究斑马鱼 SCL 在血细胞发育中的作用 cDNA 克隆将与 Core B 合作分离， 用于检查正常斑马鱼中 SCL RNA 表达的模式 发育，以及表现出的异常造血发育 无血突变体和其他斑马鱼突变体由 世界各地的调查人员。通过对小鼠 SCL 和 斑马鱼这种蛋白质在红细胞发育中的作用应该是 成立。

The nuclear regulatory proteins required for erythroid development are not entirely defined. In other developmental systems proteins of the basic helix-loop-helix (bHLH) family are often involved in specifying cell fate. The bHLH factor known as SCL (stem cell leukemia) (also known as tal- 1/TCL5) is a potential candidate for an important role in erythroid development. In this project the murine SCL gene will be inactivated by gene targeting in embryonic stem cells, and mice homozygous for deficiency of SCL will be generated. The phenotype of these mice will be characterized throughout embryogenesis and adult life (if viable). In addition, ES cells homozygous for SCL deficiency will be generated from single knock-out cells in order to assess hematopoietic and erythroid development in vitro. If the phenotypes in vitro or in vivo are not striking in the absence of SCL, a systematic search for potentially redundant proteins will be undertaken, and involve cross-breeding of SCL heterozygotes with other bHLH knock-outs (e.g. Lyl). To further investigate the role of SCL in blood cell development, a zebrafish SCL cDNA clone will be isolated in collaboration with Core B, which will be used to examine the pattern of SCL RNA expression in normal zebrafish development, and in abnormal hematopoietic development exhibited by the bloodless mutant and other zebrafish mutants to be provided from investigators worldwide. Through combined study of SCL in mice and zebrafish the role of this protein in erythroid development should be established.