pTa-controlled reporter to identify lymphoid precursor

描述(由申请人提供)：从多能干细胞发展成淋巴系是一个知之甚少的过程。与造血干细胞(HSC)相比，淋系前体细胞移植到免疫缺陷宿主后具有更快的免疫修复能力，因此识别淋巴样前体细胞不仅具有学术意义，而且具有临床意义。先前对Pre-TCRA(PTA)链的表达分析表明，它存在于T细胞的前体细胞中，而不存在于多能造血干细胞中。这表明PTA基因的表达是淋巴前体的标志。因此，我们建议借助由PTA启动子和增强子元件控制的报告基因来分离淋巴前体细胞。我们的初步数据表明，这样的报告可以在骨髓中的淋巴前体细胞中表达，这些前体能够产生所有的淋巴系，但不能产生髓系细胞。我们建议将表达报告基因的细胞细分为与淋巴发育相关的各种细胞表面分子。然后我们将揭示这些亚群的发育潜力，以便生成胎儿和成人淋巴生成中淋巴承诺的详细图像，并确定不同谱系的分支点。我们将进一步描述涉及谱系承诺的转录因子的表达和基本作用的发育阶段。

DESCRIPTION (provided by applicant): The development of lymphoid lineages from pluripotent stem cells is a poorly understood process. The identification of lymphoid committed precursors is not only of academic but also of clinical interest because of their faster immunorestorative potential when compared to hemopoietic stem cells (HSC) after transplantation into immunodeficient hosts. Previous analysis of the expression of the pre-TCRa (pTa) chain, which forms the pre-TCR in association with the TCRb chain, has shown its presence in precursors of T cells but not in pluripotent hemopoietic stem cells. This suggests that expression of the pTa gene marks lymphoid precursors. Therefore, we propose to isolate lymphoid precursors with the aid of reporter genes that are controlled by pTa promoter and enhancer elements. Our initial data indicate that such reporters can be expressed in lymphoid committed precursors in the bone marrow that are able to generate all lymphoid lineages but no myeloid cells. We propose to subdivide the reporter gene expressing cells by a variety of cell surface molecules that are involved in and correlate with lymphoid development. We will then reveal the developmental potential of these subsets in order to generate a detailed picture of lymphoid commitment in fetal and adult lymphopoiesis and to identify branching points of the various lineages. We will further characterize developmental stages with regard to expression and essential role of transcription factors involved in lineage commitment.