pTa-controlled reporter to identify lymphoid precursor

描述（由申请人提供）：从多能干细胞发育淋巴谱系是一个知之甚少的过程。淋巴定向前体细胞的鉴定不仅具有学术意义，而且具有临床意义，因为它们在移植到免疫缺陷宿主后比造血干细胞（HSC）具有更快的免疫恢复潜力。先前对与TCR b链结合形成前TCR的前TCR α（pTa）链的表达的分析已经显示其存在于T细胞的前体中，但不存在于多能造血干细胞中。这表明pTa基因的表达标志着淋巴前体。因此，我们建议与报告基因的帮助下，由pTa启动子和增强子元件控制的淋巴前体分离。我们的初步数据表明，这种报告基因可以在骨髓中的淋巴定型前体中表达，这些前体能够产生所有淋巴谱系，但不产生髓系细胞。我们建议细分的报告基因表达细胞的各种细胞表面分子参与和相关的淋巴发育。然后，我们将揭示这些子集的发展潜力，以产生一个详细的图片淋巴承诺在胎儿和成人淋巴细胞生成，并确定分支点的各种谱系。我们将进一步表征发展阶段的表达和重要作用的转录因子参与谱系承诺。

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.