Study Sox4 regulated genes in B cell development in a novel in vitro system

SunR 21项目摘要/摘要 B细胞构成免疫系统的组成部分。B细胞缺乏是原发性高血压的主要原因之一。 免疫缺陷疾病。在超过120种已知的PID中，B细胞缺陷和联合B和T细胞 其中近40个是由缺陷造成的。B细胞发育是一个连续的过程，包括： 造血干细胞、多系祖细胞、普通淋巴祖细胞、前原B （级分A）、前B（级分B和C）、早期前B（级分C '）、晚期前B（级分D）、未成熟B（级分E）、 和成熟B（级分F）。这一过程是由多个基因的协调功能精确调控的， 尤其是那些编码转录因子的基因。Sox 4是编码转录因子的基因，已知 对许多发育过程至关重要。Sox 4基因敲除会导致胚胎死亡， 心脏缺陷从Sox 4基因敲除小鼠分离的胎肝细胞不能在受体小鼠中产生B细胞 说明Sox 4的功能对于B细胞的发育是必不可少的。杀伤力 Sox 4基因常规敲除的缺失阻碍了Sox 4在B细胞发育中作用的进一步研究。我们 使用条件性基因敲除小鼠模型系统地研究了Sox 4在B细胞发育中的作用 Sox 4基因在不同发育阶段缺失。造血干细胞中的Sox 4缺失导致造血干细胞的凋亡。 几乎完全缺乏前B细胞和晚期B细胞，而前B细胞或成熟B细胞中Sox 4缺失 细胞没有可检测的影响。尽管条件性敲除模型使我们能够揭示 Sox 4的发育阶段特异性功能，B细胞的缺乏对未来的深入研究造成了障碍 问题研究为了克服这个问题，我们已经开发了一种体外培养系统，在该系统中， 发育事件依赖于Sox 4的存在。该功能系统非常适合表征 Sox 4功能的分子机制。我们已经进行了基因表达微阵列分析 使用培养的细胞和鉴定的潜在Sox 4调节基因。深入研究Sox 4的特性 功能在B细胞的发展，使用我们的新的体外系统，我们提出了这个项目的两个具体目标。 目的1是鉴定和表征由Sox 4直接调控的基因。目标2是描述两个角色的特征 Sox 4在早期B细胞发育中的下游靶点。成功完成这项研究将 阐明Sox 4调控的转录程序，推进我们对B细胞发育的理解， 扩大我们对PID的了解。

SunR21 Project Summary/Abstract B cells constitute an integral part of the immune system. B cell deficiency is one of the major causes of primary immunodeficiency diseases. Of more than 120 known PIDs, B cell deficiencies and combined B and T cell deficiencies are responsible for nearly 40 of them. B cell development is a sequential process consisting of the following stages: hematopoietic stem cell, multilineage progenitor, common lymphoid progenitor, pre-pro-B (fraction A), pro-B (fractions B and C), early pre-B (fraction C'), late pre-B (fraction D), immature B (fraction E), and mature B (fraction F). The process is precisely regulated by coordinated functioning of multiple genes, especially those encoding transcription factors. Sox4 is a gene that encodes a transcription factor and is known to be vital for many developmental processes. Sox4 conventional knockout causes embryos to die due to cardiac deficiency. Fetal liver cells isolated from Sox4 knockout mice fail to generate B cells in recipient mice after transplantation, indicating that the function of Sox4 is indispensable for B cell development. The lethality of the Sox4 conventional knockout has hindered further studies on the role of Sox4 in B cell development. We systematically investigated the role of Sox4 in B cell development using conditional knockout mouse models with Sox4 deletion at different developmental stages. Sox4 deletion in hematopoietic stem cells results in a nearly complete lack of pro-B cells and later stage B cells, whereas Sox4 deletion in pre-B cells or mature B cells has no detectable effect. Although the conditional knockout models have allowed us to reveal the developmental stage-specific functions of Sox4, the lack of B cells has imposed an obstacle for future in-depth studies. To overcome this problem, we have developed an in vitro culture system in which a stage specific developmental event is dependent on the presence of Sox4. This functional system is ideal for characterizing the molecular mechanisms underlying Sox4 function. We have performed gene expression microarray profiling using cultured cells and identified potential Sox4-regulated genes. To pursue in-depth characterization of Sox4 function in B cell development using our novel in vitro system, we propose two specific aims for this project. Aim 1 is to identify and characterize genes directly regulated by Sox4. Aim 2 is to characterize the roles of two downstream targets of Sox4 in early B cell development. Successful completion of this proposed research will elucidate the transcription program regulated by Sox4, advance our understanding of B cell development, and expand our knowledge of PIDs.