GENE ENCODING P67 MYELOID DIFFERENTIATION ANTIGEN

血浆糖蛋白的表达谱 造血细胞的膜反映了它们的状态 分化和成熟。其中许多“差异化” 抗原“首先是用单抗鉴定出来的。 利用造血细胞亚群表达分化抗原 细胞已被广泛研究，但细胞的生物学功能 这些蛋白质中的大多数都是未知的。然而，还有 越来越多的证据表明，许多这样的蛋白质证明 谱系特异的、发育受调控的表达有 反映各种效应细胞的重要生理作用 表达它们的特定白细胞的功能。P67 抗原，被CD33组单抗识别， 在髓系细胞的祖细胞上表达，并由 粒细胞系能够增殖，但不能 终末分化的粒细胞。人类基因编码 P67是在小鼠的遗传背景中被分离出来的 一系列的DNA介导的基因转移和荧光- 用CD33抗体激活细胞分选。独一无二的序列 人类p67基因座的探针是从这些第三代 小鼠细胞转化体，用于获得生物活性 编码p67的基因组克隆，并将该基因分配给 19号染色体。这个探针也被用来识别一种 HL-60细胞部分互补DNA的克隆 C DNA文库。进一步的努力将集中在获得充分的- 可用于确定初级克隆的长度cDNA克隆 P67的结构和确定外显子的组织 以及该基因的内含子。这将使未来的研究能够 阐明赋予特定表达的控制机制 未成熟髓系细胞中p67的表达。初步研究表明 P67在小鼠细胞的酪氨酸残基上被磷酸化 共表达v-fms癌基因的转化子，但p67 本身并不具有固有的酪氨酸激酶活性。这个 P67的磷酸化将在小鼠细胞中进行进一步的研究 共表达其他激活癌基因或 对受体显示酪氨酸的生长因子的反应 激活酶活性。因此，试剂在前两个阶段得到了发展 多年的获奖经验将使我能够确定初选 P67的结构，研究其在细胞增殖中的作用 在作为酪氨酸特异性激酶底物的骨髓生成过程中， 并研究该基因的转录调控。

The repertoire of glycoproteins expressed on the plasma membrane of hematopoietic cells reflects their state of differentiation and maturation. Many of these "differentiation antigens" were first identified using monoclonal antibodies. The expression of differentiation antigens by subsets of hematopoietic cells has been extensively studied, but the biologic function of the majority of these proteins is undetermined. However, there is growing evidence that many such proteins that demonstrate lineage-specific, developmentally regulated expression have important physiologic roles reflecting various effector cell functions of the particular leukocytes that express them. The p67 antigen, recognized by the CD33 group of monoclonal antibodies, is expressed on progenitors of myeloid cells and by members of the granulocytic lineage capable of proliferation, but not on terminally differentiated granulocytes. The human gene encoding p67 has been isolated in a mouse genetic background by three serial rounds of DNA-mediated gene transfer and fluorescence- activated cell sorting with a CD33 antibody. A unique sequence probe for the human p67 locus was derived from these tertiary mouse cell transformants and used to obtain biologically active genomic clones encoding p67 and to assign this gene to chromosome 19. This probe has also been used to identify a partial complementary DNA (cDNA) clone from an HL-60 cell cDNA library. Further efforts will be focused on obtaining full- length cDNA clones that can be utilized to determine the primary structure of p67 and to determine the organization of the exons and introns of this gene. This will enable future studies to elucidate the control mechanisms that confer specific expression of p67 in immature myeloid cells. Preliminary studies indicate p67 is phosphorylated on tyrosine residues in mouse cell transformants that coexpress the v-fms oncogene, but that p67 does not itself possess intrinsic tryosine kinase activity. The phosphorylation of p67 will be further studied in mouse cell transformants that are coexpressing other activated oncogenes or in response to growth factors whose receptors exhibit tyrosine kinase activity. Thus the reagents developed during the first two years of this award will allow me to determine the primary structure of p67, to investigate its role in cellular proliferation during myelopoieses as a substrate for a tyrosine-specific kinases, and to study the transcriptional regulation of this gene.