Molecular mechanisms of gamma/delta T cell lineage commitment

 描述(由申请人提供)：本方案的目标是了解控制γδT细胞承诺的分子机制，以及承诺和效应者命运规范之间的联系。越来越多的证据表明，γδ的T细胞承诺受到T细胞受体信号强度差异的影响。TCR信号强度的这些差异通过诱导E蛋白DNA结合的抑制剂ID3来指导命运。虽然E蛋白在调节谱系命运方面有明确的作用，但这些E蛋白控制的下游靶基因，以及协同调节这一过程的转录调控因子仍然未知。这些命运决定太复杂了，不能集中在单个基因或途径上，需要一种基于网络的综合方法。γδT细胞效应器的命运也在胸腺中确定，并受TCRs信号的影响；然而，对γδT细胞谱系的承诺与获得效应器命运之间的关系尚未得到正式检验。由于缺乏一种分子指示剂来识别不可逆转地致力于γδT细胞谱系的γδT细胞前体，使得深入了解控制γδT细胞承诺的分子机制以及承诺与效应者命运规范之间的联系的努力受到了混乱。CD73最近被确定为γδT细胞前体细胞的标志物，并将被用来解决这些问题。在目标1中，将根据CD73的表达分离未承诺和承诺的γδTcr+祖细胞，以构建与γδT细胞承诺相关的E蛋白靶标和协同转录因子的全面、全基因组网络，然后将测试它们在协调γδ谱系承诺中的作用。在目标2中，TcR信号将在γδT细胞谱系承诺的同时和之后发生改变，以确定承诺和效应者的命运是同时分配还是顺序分配。总而言之，这些努力将为如何控制γδT细胞的发育提供关键信息。

 DESCRIPTION (provided by applicant): The goal of this proposal is to understand the molecular mechanisms that control γδ T cell commitment and the link between commitment and effector fate specification. There is growing evidence suggesting that γδ T cell commitment is influenced by differences in T cell receptor (TCR) signal strength. These differences in TCR signal strength instruct fate through induction of Id3, an inhibitor of E protein DNA binding. Whil E proteins have a clear role in regulating lineage fate decisions, the downstream target genes that these E proteins control, as well as the transcriptional regulators that cooperate to mediate this process, remain unknown. These fate decisions are too complex to focus on a single gene or pathway and require a comprehensive, network-based approach. γδ T cell effector fate is also specified in the thymus and is influenced by TCR signaling; however, the relationship between commitment to the γδ T cell lineage and acquisition of effector fate has not been formally tested. Efforts to gain insight into the molecular mechanisms that govern γδ T cell commitment, as well as the link between commitment and effector fate specification, have been confounded by the lack of a molecular indicator that identifies γδ T cell progenitors that have irreversibly committed to γδ T cell lineage. CD73 has recently been identified as a marker of committed γδ T cell progenitors and will be utilized to address these questions. In Aim 1, uncommitted and committed γδTCR+ progenitors will be isolated based on CD73 expression to construct a comprehensive, genome-wide network of E protein targets and cooperating transcription factors associated with γδ T cell commitment that will then be tested for their rols in orchestrating γδ lineage commitment. In Aim 2, TCR signaling will be altered concurrent with and following commitment to the γδ T cell lineage to determine if commitment and effector fate are assigned simultaneously or sequentially. Collectively, these efforts will provide critical insiht into how development of γδ T cells is controlled.