Molecular cloning of complementary DNAs encoding the heavy chain of the human 4F2 cell-surface antigen: a type II membrane glycoprotein involved in normal and neoplastic cell growth.

Complementary DNA (cDNA) clones encoding the heavy chain of the heterodimeric human membrane glycoprotein 4F2 have been isolated by immunoscreening of a lambda gt11 expression library. The identity of these clones has been confirmed by hybridization to RNA and DNA prepared from mouse L-cell transfectants, which were produced by whole cell gene transfer and selected for cell-surface expression of the human 4F2 heavy chain. DNA sequence analysis suggests that the 4F2 heavy-chain cDNAs encode an approximately 526-amino acid type II membrane glycoprotein, which is composed of a large C-terminal extracellular domain, a single potential transmembrane region, and a 50-81 amino acid N-terminal intracytoplasmic domain. Southern blotting experiments have shown that the 4F2 heavy-chain cDNAs are derived from a single-copy gene that has been highly conserved during mammalian evolution.