Functional analysis of Th-POK in T cell development

Th-POK 在 T 细胞发育中的功能分析

• 批准号: 18590472
• 负责人: SUZUKI Harumi
• 金额: $ 2.57万
• 依托单位: Research Institute, International Medical Center of Japan
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18590472/
• 关键词: T lymphocyte; ThPOK; transcription factor; signal transduction; CD4; CD8

Zinc finger transcription factor Th-POK has been identified as a master regulator of CD4/CD8 lineage commitment in the thymus. It is required for the differentiation of CD4 single positive T cells and its expression converts lineage fate from CD8-SP to CD4-SP. Despite the interesting phenotypes of Th-POK mutant mice, its function in thymocyte lineage commitment is completely unknown. In order to investigate the function of each domain of Th-POK, we introduced various mutant Th-POK cDNAs into Pax5 deficient proB cells and reconstituted the thymus with these cells. We found that the lineage converting activity of Th-POK requires its BTB domain and Zn finger domain. In order to identify downstream targets of Th-POK, we next performed chromatin immunoprecipitation experiments using anti-Th-POK antibody. By this method we found that Th-POK binds directly to the distal promoter region of the Runx3 gene. Therefore Th-POK could directly suppress expression of Runx3, which is required for CD4 repression in DP thymocyte. Furthermore, we found that calcium ionophore as well as some apoptosis inducing agents induced transcription of Th-POK in unsignaled DP thymocytes. Induction of apoptosis in DP thymocytes is induced by strong TCR-signals and differentiation to CD4-SP lineage requires a stronger (or longer) TCR-signal than the one required for the CD8-SP lineage. Therefore, it would be interesting if induction of Th-POK and induction of apoptosis share some part of the same signaling pathway in DP thymocytes.

锌指转录因子 Th-POK 已被确定为胸腺中 CD4/CD8 谱系定型的主要调节因子。它是 CD4 单阳性 T 细胞分化所必需的，其表达将谱系命运从 CD8-SP 转变为 CD4-SP。尽管 Th-POK 突变小鼠具有有趣的表型，但其在胸腺细胞谱系定型中的功能完全未知。为了研究Th-POK每个结构域的功能，我们将各种突变的Th-POK cDNA引入Pax5缺陷的proB细胞中，并用这些细胞重建胸腺。我们发现Th-POK的谱系转换活性需要其BTB结构域和Zn指结构域。为了确定 Th-POK 的下游靶标，我们接下来使用抗 Th-POK 抗体进行了染色质免疫沉淀实验。通过这种方法，我们发现 Th-POK 直接结合到 Runx3 基因的远端启动子区域。因此，Th-POK 可以直接抑制 Runx3 的表达，而 Runx3 是 DP 胸腺细胞中 CD4 抑制所必需的。此外，我们发现钙离子载体以及一些细胞凋亡诱导剂在无信号的 DP 胸腺细胞中诱导 Th-POK 的转录。 DP胸腺细胞凋亡的诱导是由强TCR信号诱导的，并且分化为CD4-SP谱系需要比CD8-SP谱系所需的更强（或更长）的TCR信号。因此，如果 DP 胸腺细胞中 Th-POK 的诱导和细胞凋亡的诱导共享相同信号通路的某些部分，将会很有趣。

项目成果

The p85a regulatory subunit of classIA phosphoinositide 3-kinase regulates b-selection in thymocyte development

IA 类磷酸肌醇 3 激酶的 p85a 调节亚基调节胸腺细胞发育中的 b 选择

• 发表时间: 2007
• 期刊: J.Immunol. 178
• 作者: Shiroki;F.;et. al.
• 通讯作者: et. al.

Rac1-mediated Bcl-2 induction is critical in antigen-induced CD4 single-positive differentiation of a CD4+CD8+ immature thymocyte line.

Rac1 介导的 Bcl-2 诱导对于抗原诱导的 CD4 CD8 未成熟胸腺细胞系的 CD4 单阳性分化至关重要。

• DOI: 10.1189/jlb.1005585
• 发表时间: 2007
• 期刊: Journal of leukocyte biology
• 影响因子: 5.5
• 作者: Oda,Hiroyo;Suzuki,Harumi;Sakai,Kouhei;Kitahara,Seiji;Patrick,MichaelS;Azuma,Yoshinao;Sugi,Kazuro;Kitamura,Toshio;Kaye,Jonathan;Shirai,Mutsunori
• 通讯作者: Shirai,Mutsunori

「研究成果報告書概要(和文)」より

摘自《研究结果报告摘要（日文）》

• 发表时间: 2005
• 作者: Kawauchi;et. al.;Nishimura et al.;Dezawa et al.;Yoshizawa et al.;星野 幹雄;星野 幹雄
• 通讯作者: 星野 幹雄

Cross-positive selection of thymocytes expressing a single T cell receptor by multiple major histocompatibility complex molecules of both classes : Implications for CD4+ vs.CD8+ lineage commitment

通过两类多个主要组织相容性复合物分子表达单一 T 细胞受体的胸腺细胞的交叉阳性选择：对 CD4 与 CD8 谱系定型的影响

• 发表时间: 2006
• 期刊: J.Immunol. 176
• 作者: Eshima;K.et al.
• 通讯作者: K.et al.

Racl mediated Bcl-2 induction is critical in antigen-induced CD4 single positive differentiation of a CD4+CD8+immature thymocyte line

Racl 介导的 Bcl-2 诱导对于抗原诱导的 CD4 CD8 未成熟胸腺细胞系的 CD4 单阳性分化至关重要

• 发表时间: 2007
• 期刊: J.Leuko.Biol. 81
• 作者: Oda;H.;et. al.
• 通讯作者: et. al.