title: Primary structure of the human 4F2 antigen heavy chain predicts a transmembrane protein with a cytoplasmic NH2 terminus.
abstract: 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.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D004262:DNA Restriction Enzymes; D006801:Humans; D007739:L Cells / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000954:Antigens, Surface; D046911:Macromolecular Substances; D008565:Membrane Proteins; D012333:RNA, Messenger; D004247:DNA; D004262:DNA Restriction Enzymes