Biochemical Studies of Human Cell Surface Markers

T淋巴细胞在胸腺中成熟，在胸腺环境的影响下，它们在胸腺中经历一系列分化、扩增和选择事件。本提案的主要目的是研究CD 3 γ、δ和CD 4基因表达的调节。CD 3基因从TCR前阶段开始参与胸腺内分化，可能更早。因此，CD 3 γ、δ和CD 3 γ在阳性和阴性选择过程中至关重要。在T淋巴细胞发育的后期阶段，CD 3蛋白控制TCR/CD 3复合物的表面表达，并且对于抗原/MHC驱动的信号转导是必不可少的。以前，我们已经表明，CD 3 γ，δ和CD 3 β基因紧密地分布在人类染色体11 q23（小鼠染色体9）的一个小簇中。CD 3 γ和δ的转录是发散的，它们的转录起始位点相距1.2至1.4 kb。CD 3 β基因位于CD 3 δ基因下游26 kb处，并以CD 3 γ基因的方向转录。尽管CD 3 γ、δ和CD 3 γ基因主要在胸腺衍生的淋巴细胞中表达，但在人和鼠活化的自然杀伤细胞中发现了CD 3 γ。尽管这三个基因在组织分布和聚类方面具有相似性，但我们的研究清楚地表明它们各自的调控元件是不同的。因此，我们对CD 3 γ、δ、CD 3 β基因簇的兴趣不仅在于其基因产物的重要功能，还在于其表达的独特发育调控。我们的第一个假设是，CD 3 γ，δ和CD 3 γ的表达是由独特的T细胞特异性机制，除了共同的元素。第二种假设是，前体T细胞中CD 3 γ、δ或CD 3 γ的诱导利用不同的途径。我们具体建议：1研究T细胞特异性的CD 3 δ基因的转录调控; 2研究T细胞和NK细胞中CD 3 γ基因表达的分子机制; 3表征参与T细胞特异性表达CD 3 γ基因的转录元件; 4研究CD 3 γ、δ和γ基因在早期淋巴细胞发育过程中的调控。

T lymphocytes mature in the thymus, where they undergo a series of differentiation, expansion and selection events under the influence of the thymic environment. The main objective of this proposal is to study regulation of expression of the CD3gamma, delta and epsilon genes. The CD3 genes are involved in intrathymic differentiation from the pre-TCR phase on and perhaps earlier. Thus, CD3gamma, delta and epsilon are of paramount importance in positive and negative selection processes. At later stages of T lymphocyte development, the CD3 proteins control surface expression of the TCR/CD3 complex and are indispensable for antigen/MHC driven signal transduction. Previously, we had shown that the CD3gamma, delta and epsilon genes map closely together in a small cluster on human chromosome 11q23 (mouse chromosome 9). CD3 gamma and delta are transcribed divergently, their transcription start sites being 1.2 to 1.4 kb apart. The CD3epsilon gene is located 26 kb downstream from the CD3delta gene and is transcribed in the direction of the CD3gamma gene. Although the CD3gamma, delta and epsilon genes are primarily expressed in thymus derived lymphocytes, CD3epsilon has been found in human and murine activated natural killer cells. In spite of the similarities in tissue distribution and the clustering of these three genes, our studies have clearly demonstrated that their respective regulatory elements are distinct. Our interest in the CD3gamma, delta, epsilon genes cluster lies therefore not only in the important functions of their gene products, but also in the unique developmental regulation of their expression. Our first hypothesis is that expression of CD3gamma, delta and epsilon is governed by unique T cell specific mechanisms in addition to common elements. A second hypothesis is that induction of CD3gamma, delta or epsilon in the precursor T cell utilizes distinct pathways. We specifically propose to: 1 Study T cell specific transcriptional regulation of the CD3delta gene; 2 Investigate the molecular mechanisms that govern expression of the CD3epsilon gene in T and NK cell; 3 Characterize transcriptional elements involved in T cell specific expression of the CD3gamma gene; 4 Examine the regulation of the CD3gamma, delta and epsilon genes during early lymphocyte development.