GENE ENCODING P67 MYELOID DIFFERENTIATION ANTIGEN

血浆中表达的糖蛋白库 造血细胞的膜反映了它们的状态， 分化和成熟。 许多“差异化” “抗原”首先使用单克隆抗体鉴定。 的 造血细胞亚群分化抗原的表达 细胞已经被广泛研究，但细胞的生物学功能 这些蛋白质中的大多数是未确定的。 不过有 越来越多的证据表明， 谱系特异性的、发育调节的表达具有 反映各种效应细胞重要生理作用 表达它们的特定白细胞的功能。 p67 抗原，由CD 33组单克隆抗体识别， 在骨髓细胞的祖细胞上表达， 粒细胞谱系能够增殖，但不能在 终末分化的粒细胞。 人类基因编码 p67已经在小鼠遗传背景中通过三种方法分离出来。 一系列的DNA介导的基因转移和荧光 用CD 33抗体激活细胞分选。 独特序列 人p67基因座的探针来源于这些三级 小鼠细胞转化体，并用于获得生物活性 编码p67的基因组克隆，并将该基因分配给 19号染色体。 该探针还用于识别 从HL-60细胞中克隆了一个部分互补DNA（cDNA cDNA文库 进一步的努力将集中在获得充分的- 长度cDNA克隆，可用于确定主要的 p67的结构，并确定外显子的组织 和这个基因的内含子。 这将使未来的研究， 阐明赋予特定表达的控制机制 p67在未成熟骨髓细胞中的表达。 初步研究表明 小鼠细胞中p67酪氨酸残基磷酸化 共表达v-fms癌基因的转化体，但p67 本身不具有固有的酪氨酸激酶活性。 的 p67的磷酸化将在小鼠细胞中进一步研究 共表达其他活化癌基因的转化体，或 对受体呈现酪氨酸的生长因子的反应 激酶活性 因此，在前两个时期开发的试剂 多年的获奖经验将使我能够决定 p67的结构，以研究其在细胞增殖中的作用 在骨髓生成过程中作为酪氨酸特异性激酶的底物， 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.