Hsal 2, A Novel Homeobox Gene in Hematopoiesis

这项提议的长期目标是确定Hsal2在骨髓生成中的作用。Hsal2是最近推出的 在果蝇中鉴定出与SAL同源框基因序列同源的分化同源框基因。 Hsal家族成员突变导致多器官发育的Townes-Brockes综合征 缺陷。Hsal2在包括造血组织在内的大多数人体组织中都有表达。几行 有证据表明Hsal2可能参与了骨髓生成：(1)Hsal2的转录调控是 由两个独立的启动子控制，并且两个启动子都带有多个假定的结合位点 对骨髓生成至关重要的调控基因，包括Wilms肿瘤抑制基因(WT-1)和维甲酸 受体c_(RAR)；(2)WT_1抑制Hsal2启动子活性，而维甲酸(RA)激活Hsal2 在荧光素酶报告基因系统中的表达；(3)Hsal2的表达与髓系一致 (4)Hsal2基因缺失小鼠的髓系数量显著减少。因此，我假设 细胞内的WT1/RAR-a/Hsal2通路可能在正常造血中起作用。生物学的 通过Hsal2亚型在造血干细胞中的过表达研究Hsal2在骨髓生成中的作用 细胞、髓系细胞系和四环素诱导的胚胎干细胞的体外培养，并鉴定 体内Hsal2基因缺失的小鼠。我们将继续重点研究Hsal2的转录调控。 WT1与RAR-m结合部位的鉴定WT1与RAR-t的拮抗作用 通过WT1在髓系细胞系中的过表达将进一步探讨Hsal2的表达。《知识》 这些研究获得的结果将有助于更好地理解对正常造血至关重要的途径 并有助于开发抗击白血病的新策略。首席调查员李猜博士将进行 在赞助商黛安·克劳斯博士和一个咨询委员会的指导下进行的实验室研究。在……里面 此外，这项提议的另一个目标是作为一种工具，将候选人发展为 在造血和白血病领域的独立和富有成效的研究人员。

The long-term goal of this proposal is to define the role of Hsal2 in myelopoiesis. Hsal2 is a recently identified divergent homeobox gene that has sequence homology to the Sal homeobox gene in Drosophila. Mutations of Hsal family member lead to Townes-Brockes syndrome with multiple organ developmental defects. Hsal2 expression is present in most human tissues including hematopoietic tissues. Several lines of evidence suggest that Hsal2 may be involved in myelopoiesis: (1) The transcriptional regulation of Hsal2 is controlled by two independent promoters and both promoters bear multiple putative binding sites for regulatory genes critical for myelopoiesis, including Wilms' tumor suppression gene (WT 1) and retinoic acid receptor-c_ (RAR); (2) WT 1 represses both Hsal2 promoter activities while retinoic acid (RA) activates Hsal2 expression in a luciferase reporter gene system; (3) Hsal2 expression coincides with the myeloid lineage commitment; (4) The myeloid population in Hsal2-null mice is significant reduced. Therefore, I hypothesize that an intracellular WT 1/RAR-a/Hsal2 pathway may play a role in normal hematopoiesis. The biological function of Hsal2 in myelopoiesis will be studied by overexpression of Hsal2 isoforms in hematopoietic stem cells, myeloid cell lines, and tetracycline-inducible embryonic stem cells in vitro, and characterization of Hsal2-null mice in vivo. We will continue to characterize the transcriptional regulation of Hsal2 with a focus on identification of the binding sites of WT1 and RAR-m The antagonistic effect between WT1 and RAR-_t on Hsal2 expression will be further explored by overexpression of WT1 in myeloid cell lines. The knowledge gained by these studies will contribute to better understanding of pathways critical for normal hematopoiesis and help to develop novel strategies to combat leukemia. The principal investigator, Dr. Li Chai will conduct the laboratory research under the guidance of a sponsor, Dr. Diane Krause, and an advisory committee. In addition, a further objective of this proposal is to serve as a vehicle for the development of the candidate into an independent and productive investigator in the area of hematopoiesis and leukemogenesis.