Hsal 2, A Novel Homeobox Gene in Hematopoiesis

Hsal 2，一种新的造血同源盒基因

• 批准号: 7095228
• 负责人: Li Chai
• 金额: $ 13.07万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7095228
• 关键词: DNA footprinting; binding sites; cell differentiation; cell line; embryonic stem cell; gel mobility shift assay; gene expression; genetic manipulation; genetic mapping; genetic regulation; genetic transcription; genetically modified animals; hematopoiesis; hematopoietic stem cells; homeobox genes; laboratory mouse; leukocytes; nuclear receptors; protein isoforms; retinoid binding proteins; tissue /cell culture; tumor suppressor genes

DESCRIPTION (provided by applicant): 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-alpha (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-alpha. The antagonistic effect between WT1 and RAR-alpha 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 candidate, 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.

描述（由申请人提供）： 该提案的长期目标是明确 Hsal2 在骨髓生成中的作用。 Hsal2 是最近发现的一种不同的同源盒基因，与果蝇中的 Sal 同源盒基因具有序列同源性。 Hsal家族成员的突变导致汤斯-布洛克斯综合征并伴有多器官发育缺陷。 Hsal2表达存在于大多数人体组织中，包括造血组织。多项证据表明，Hsal2 可能参与骨髓细胞生成：（1）Hsal2 的转录调控由两个独立的启动子控制，两个启动子均具有多个对骨髓细胞生成至关重要的调控基因的假定结合位点，包括肾母细胞瘤抑制基因（WT 1）和视黄酸受体-α（RAR）； (2) WT 1 抑制 Hsal2 启动子活性，而视黄酸 (RA) 激活荧光素酶报告基因系统中的 Hsal2 表达； (3) Hsal2表达与骨髓谱系定型一致； (4)Hsal2缺失小鼠的髓系细胞群显着减少。因此，我推测细胞内WT 1/RAR-a/Hsal2通路可能在正常造血过程中发挥作用。将通过体外造血干细胞、骨髓细胞系和四环素诱导胚胎干细胞中 Hsal2 同工型的过表达以及 Hsal2 缺失小鼠的体内表征来研究 Hsal2 在骨髓生成中的生物学功能。我们将继续表征 Hsal2 的转录调控，重点是鉴定 WT1 和 RAR-α 的结合位点。通过在骨髓细胞系中过度表达WT1，将进一步探讨WT1和RAR-α对Hsal2表达的拮抗作用。这些研究获得的知识将有助于更好地理解正常造血的关键途径，并有助于制定对抗白血病的新策略。候选人柴力博士将在赞助商黛安·克劳斯博士和顾问委员会的指导下进行实验室研究。此外，该提案的另一个目标是作为将候选人发展为造血和白血病发生领域的独立且富有成效的研究者的工具。