Szala S, Froehlich M, Scollon M, Kasai Y, Steplewski Z, Koprowski H, Linnenbach A J
Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104.
Proc Natl Acad Sci U S A. 1990 May;87(9):3542-6. doi: 10.1073/pnas.87.9.3542.
Defined by monoclonal antibody GA733, the GA733-2 antigen is a cell surface 40-kDa glycoprotein associated with human carcinomas of various origins. Molecular clones for the GA733-2 antigen were isolated from a colorectal carcinoma cell line cDNA library using the high-efficiency COS cell expression system. A 1.4-kilobase cDNA species was enriched by immunoselection with monoclonal antibody. The authenticity of individual clones was established by immunologic and sequence criteria. At the amino acid sequence level, GA733-2 was found to be greater than 99% identical to the previously described KSA antigen defined by monoclonal antibody KS1/4. The amino acid sequence derived from the previously described GA733-related gene, GA733-1, was found to be 49% identical to GA733-2. The positions of 12 cysteine residues in the extracellular domains of the two GA733 antigens are conserved, as is the overall distribution of hydrophobic and hydrophilic residues. A 1.45-kilobase transcript of the GA733-2/KSA gene was found to be expressed in cell lines derived from colorectal and pancreatic carcinoma.
GA733 - 2抗原由单克隆抗体GA733界定，是一种与各种起源的人类癌相关的细胞表面40 kDa糖蛋白。使用高效COS细胞表达系统，从结肠癌细胞系cDNA文库中分离出GA733 - 2抗原的分子克隆。通过用单克隆抗体进行免疫选择，富集了一个1.4千碱基的cDNA物种。通过免疫学和序列标准确定了各个克隆的真实性。在氨基酸序列水平上，发现GA733 - 2与先前由单克隆抗体KS1/4界定的KSA抗原的同一性大于99%。发现源自先前描述的GA733相关基因GA733 - 1的氨基酸序列与GA733 - 2的同一性为49%。两种GA733抗原细胞外结构域中12个半胱氨酸残基的位置是保守的，疏水和亲水残基的总体分布也是如此。发现GA733 - 2/KSA基因的一个1.45千碱基转录本在源自结肠和胰腺癌的细胞系中表达。
