Bergsagel P L, Victor-Kobrin C, Timblin C R, Trepel J, Kuehl W M
Navy Medical Oncology Branch, National Cancer Institute, Bethesda, MD 20889-5105.
J Immunol. 1992 Jan 15;148(2):590-6.
Using a subtractive cDNA approach, we have identified a number of genes expressed in murine plasmacytomas, but not B or pre-B lymphomas. One of these genes, 289A, expresses a 1.8-kb microsomally localized mRNA that encodes a 314-amino-acid protein containing a signal sequence and a hydrophobic transmembrane domain. Sequence comparison suggests that the predicted protein is the murine homologue of a human cell surface pan-epithelial glycoprotein known variously as EGP, GA733-2, KSA, and KS1/4, recognized by mAb HEA125, GA733, KS1/4, CO17-1A, M74, and 323/A3. The 289A mRNA is highly expressed in normal murine tissues containing epithelial cells, and at a low level in plasma cells induced by LPS stimulation of spleen B lymphocytes. It is expressed in 15 of 16 plasmacytomas, but at a much lower level, if at all, in pre-B or B lymphomas. In human B cell lines, 289A detects a 1.5-kb mRNA in the myeloma cell line 8226, but not in Burkitt's lymphoma or lymphoblastoid cell lines. Subsequent FACS analysis of human cell lines with the mAb GA733 and KS1/4 demonstrated concordant expression of the mRNA and the protein. We conclude that 289A is the murine homologue of EGP, GA733-2, KSA, and KS1/4 Ag. Although its expression was previously thought to be restricted to epithelial cells, it is also expressed in plasma cells and is a B lymphocyte differentiation Ag. Because of the multiplicity of names, we propose calling the human gene hEGP314, and the murine gene mEGP314.
采用消减cDNA方法，我们鉴定出了一些在小鼠浆细胞瘤中表达，但在B或前B淋巴瘤中不表达的基因。其中一个基因289A表达一种1.8kb的定位于微粒体的mRNA，它编码一个含信号序列和疏水跨膜结构域的314个氨基酸的蛋白质。序列比较表明，预测的蛋白质是一种人类细胞表面泛上皮糖蛋白的小鼠同源物，该糖蛋白有多种名称，如EGP、GA733-2、KSA和KS1/4，可被单克隆抗体HEA125、GA733、KS1/4、CO17-1A、M74和323/A3识别。289A mRNA在含有上皮细胞的正常小鼠组织中高表达，在脂多糖刺激脾B淋巴细胞诱导产生的浆细胞中低表达。它在16个浆细胞瘤中的15个中表达，但在前B或B淋巴瘤中，即便有表达，水平也低得多。在人B细胞系中，289A在骨髓瘤细胞系8226中检测到一个1.5kb的mRNA，但在伯基特淋巴瘤或淋巴母细胞系中未检测到。随后用单克隆抗体GA733和KS1/4对人细胞系进行的荧光激活细胞分选分析表明，mRNA和蛋白质的表达一致。我们得出结论，289A是EGP、GA733-2、KSA和KS1/4抗原的小鼠同源物。尽管其表达以前被认为仅限于上皮细胞，但它也在浆细胞中表达，并且是一种B淋巴细胞分化抗原。由于名称繁多，我们建议将人类基因命名为hEGP314，将小鼠基因命名为mEGP314。
