在血液系统中，转录因子Hoxb5特异表达于造血干细胞(HSC)，是LT-HSC的重要分子标记。Hoxb5是否参与调控HSC功能尚不清楚。我们初步通过逆转录病毒载体在HSC过表达Hoxb5，发现Hoxb5促进HSC进入细胞周期，并且抑制B淋系造血。为深入研究Hoxb5对HSC功能影响及机制，本研究将已建立的ROSA26位点Hoxb5敲进小鼠模型(LSL-Hoxb5)，分别与Vav1/Mx1/CD19-Cre鼠杂合实现Hoxb5在血液系统或B淋系特异性过表达。借助流式免疫表型分析、系列移植、竞争性移植、及CFU实验等明确过表达Hoxb5对HSC自我更新及谱系分化影响。运用RNA-Seq及生物信息学解析Hoxb5调控HSC及B淋系的信号通路。本研究将深入阐明Hoxb5对HSC功能及B淋系造血的影响及机制，为HSC功能调控及B淋系造血增加新的理论认识。

In hematopoietic system, Hoxb5 is preferentially expressed in hematopoietic stem cells(HSCs), and is a key marker of LT-HSCs. Based on our preliminary data, overexpression of Hoxb5 drove HSCs into cell cycle, and blocked B lymphopoiesis. To date, the exact role and related molecular mechanisms of Hoxb5 on hematopoisis remain elusive. We had constructed Hoxb5 knock in mouse model(LSL-Hoxb5). In combination with Vav1, Mx1, and CD19-Cre mouse lines, we attempt to achieve ectopic expression of Hoxb5 in hematopoietic stem cells and offspring or B lymphoid lineage. We will investigate the effects of overexpressing Hoxb5 in hematopoietic stem cells and B lymphopoiesis, by approaches of serial transplantation and flow cytometric analysis. RNA-Seq and bioinformatic analysis will be used to illustrate the profiling of Hoxb5 signal pathways in HSCs. Our study will elucidate the role and mechanism of Hoxb5 in regulating HSCs and B lymphopoiesis.