SIGNAL TRANSDUCTION MOLECULES ON MOUSE NK CELLS

自然杀伤(NK)细胞是大颗粒细胞的一个亚群 淋巴细胞(LGL)能够识别和溶解各种不同的 病毒感染或肿瘤靶细胞，以及某些 未发生过敏性或主要组织相容性的微生物 复合体(MHC)-限制。NK细胞不重排T细胞受体 基因，并且不表达细胞表面的TCR分子或成分 分化簇3(CD3)转导复合体。NK细胞可以 表达信号转导分子，包括CD2、CD16和CD45。 然而，在这些细胞中，只有CD45不是NK细胞特异性的。随着使用 一种抗大鼠IL-2激活的NK细胞的单抗，我们有 最近发现了一种在NK细胞上高表达的30kD蛋白 细胞。这种蛋白质的功能是二硫键连接的二聚体，能够 调节NK细胞的跨膜信号转导。此外，我们还拥有 克隆并测序了编码这一新的信号转导的基因 大鼠体内的分子。因为它的生物活性和它的 在序列上的唯一性，这种蛋白质可以被认为是新的 受体复合体，选择性表达于NK细胞(NKR)。由于 该蛋白(PI)在NK细胞中可能具有的重要功能 介导的细胞毒活性，我们决定克隆小鼠NKR-P1 同源。小鼠是一种研究更广泛的动物模型，而不是 并允许我们进行目前几乎是 不可能在老鼠身上成功完成。最近，由 NKR-P1大鼠基因与小鼠CDNA的交叉杂交 文库由高度纯化的白介素2(IL-2)激活而成， 小鼠NK细胞，我们成功地克隆了小鼠 NKR-P1作为CDNA和基因组基因的同源物。三个相似的 消息在大小和序列上不同，在小鼠体内共同转录 NK细胞。通过使用针对每个共同表达的 转录本，我们能够将所有3个基因定位到一个共同的片段 6号染色体上与NK1.1紧密连锁的区域 被映射。编码NK1.1抗原的基因尚未被克隆。在……上面 在这些结果的基础上，我们现在感觉到我们处于 更准确地聚焦我们项目的目标。这些目标将是：1) 小鼠NKR-P1基因家族功能的初步研究 与NK1.1和NK2.1抗原的关系；2)克隆启动子 基因组中三个共转录的小鼠NKR-P1基因的区域 我们分离的克隆并试图描述一种交易因子 对所有人都是通用的；以及3)使用 不同大小的构造，源自可用的5‘上游 区域片段，以更好地研究这些基因的调控。我们是 相信这些测试提供的信息将澄清 发挥了NKR-P1的生理作用，并导致了对如何 利用它在体内的功能。

Natural killer (NK) cells are a subpopulation of large granular lymphocytes (LGL) that are able to recognize and lyse a wide variety of virally infected or neoplastic target cells, as well as certain microorganisms without previous sensitization or major histocompatibility complex (MHC)-restriction. NK cells do not rearrange T-cell receptor genes, and do not express cell surface TcR molecules or components of the cluster-of-differentiation 3 (CD3) transduction complex. NK cells do express signal transduction molecules, including CD2, CD16, and CD45. Among these, only CD45, however, is not NK cell specific. With the use of a monoclonal antibody against rat IL-2 activated NK cells, we have recently identified a 30 kD protein which is highly expressed on NK cells. This protein functions as a disulfide linked dimer capable of mediating transmembrane signalling in NK cells. Furthermore, we have cloned and sequenced the gene encoding this novel signal transduction molecule in the rat. Because of its biological activity and its uniqueness in sequence, this protein may be considered part of a new receptor complex,selectively expressed on NK cells (NKR). Due to the important function that this protein (PI) may have in the NK cell mediated cytotoxic activity, we decided to clone the mouse NKR-P1 homologue. The mouse is a more extensively studied animal model than the rat and allows us to perform experiments that are currently almost impossible to be successfully accomplished in the rat. More recently, by cross-hybridizing the NKR-P1 rat gene to the mouse CDNA present in a library generated from highly purified, interleukin-2 (IL-2) activated, mouse Natural Killer (NK) cells, we succeeded in cloning the mouse homologue of NKR-P1 as both CDNA and genomic genes. Three similar messages, differing in size and sequence, are co-transcribed in the mouse NK cells. By using probes specific for each of the co-expressed transcripts, we were able to map all 3 of these genes to a common segment of chromosome 6 closely linked to the region where NK1.1 is believed to be mapped. The gene encoding NK1.1 antigen has not yet been cloned. On the basis of these results, we now feel that we are in the position of focusing the aims of our project more precisely. These aims will be: 1) to study the function of mouse NKR-P1 gene family by first defining its relationship to the NK1.1 and NK2.1 antigens; 2) to clone the promotor region of all three co-transcribed mouse NKR-P1 genes from the genomic clones we have isolated and attempt to characterize a transacting factor common to all of them; and 3) to generate transgenic mice using constructs of different sizes, derived from the available 5' upstream region segments, to better study the regulation of these genes. We are confident that the information provided by these tests will clarify the physiological role played y NKR-P1 and lead to insights as to how to exploit its function in vivo.