Genetics of the cell surface: Assignment of genes coding for external membrane proteins to human chromosomes 10 and 14

Using somatic cell hybridization gene mapping methodology, genes coding for human cell-surface proteins have been assigned to specific chromosomes. Lactoperoxidase-catalyzed iodination was employed to label external membrane proteins in cell hybrids between mouse and human cultured cells. Mouse and human external membrane proteins were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis. After electrophoresis, external membrane proteins were identified by autoradiography. An external membrane protein of 130,000 molecular weight (EMP-130) segregated concordantly with glutamic oxaloacetic transaminase_s (GOT_s, EC 2.6.1.1), an enzyme marker encoded on chromosome 10. External membrane proteins of 195,000 and 175,000 molecular weight (EMP-195 and EMP-175) segregated concordantly with nucleoside phosphorylase (NP, EC 2.4.2.1), an enzyme marker encoded on chromosome 14. Limited proteolysis of the 195,000 and 175,000 molecular weight proteins suggests that these two proteins are modified forms of each other and are encoded by the same locus. These findings demonstrate the mapping of human genes coding for external proteins EMP-130 and EMP-195 to chromosomes 10 and 14, respectively. Chromosome analyses of cell hybrids supported these assignments.