Teixeira S, Di Grandi S, Kühn L C
J Biol Chem. 1987 Jul 15;262(20):9574-80.
The human cell surface antigen 4F2 is a disulfide-linked heterodimer consisting of a glycosylated heavy chain and a nonglycosylated light chain. The antigen is ubiquitously expressed on proliferating cells but only in resting cells from certain tissues. Its function has been proposed to relate to cellular Ca2+/Na+ exchange. We describe the molecular cloning of the 4F2 heavy chain gene and cDNA by a gene transfer approach. Part of the gene was isolated from a genomic lambda library constructed with DNA of a secondary transfectant L cell line that expresses 4F2 antigen. A gene-specific probe derived from the phage inserts was used to isolate two full length cDNA clones. Both cDNA clones directed the expression of 4F2 antigen in transfected mouse L cells. The 4F2 antigen heavy chain gene specifies a 2.1-kilobase mRNA with an open reading frame coding for a 529-residue protein of 58 kDa. The protein lacks an NH2-terminal signal peptide but contains an internal transmembrane-spanning region and four potential glycosylation sites in its COOH-terminal domain. We predict that the 4F2 antigen heavy chain is a transmembrane protein with a cytoplasmic NH2 terminus of 81 amino acids. The antigen shows no homology to known protein sequences.
人细胞表面抗原4F2是一种由糖基化重链和非糖基化轻链通过二硫键连接而成的异二聚体。该抗原在增殖细胞中普遍表达，但仅在某些组织的静止细胞中表达。有人提出其功能与细胞Ca2+/Na+交换有关。我们通过基因转移方法描述了4F2重链基因和cDNA的分子克隆。该基因的一部分是从用表达4F2抗原的二次转染L细胞系的DNA构建的基因组λ文库中分离出来的。用来自噬菌体插入片段的基因特异性探针分离出两个全长cDNA克隆。两个cDNA克隆都在转染的小鼠L细胞中指导4F2抗原的表达。4F2抗原重链基因指定了一个2.1千碱基的mRNA，其开放阅读框编码一个58 kDa的529个残基的蛋白质。该蛋白质缺乏NH2末端信号肽，但在其COOH末端结构域含有一个内部跨膜区域和四个潜在的糖基化位点。我们预测4F2抗原重链是一种跨膜蛋白，其细胞质NH2末端有81个氨基酸。该抗原与已知蛋白质序列无同源性。
