title: Expression of hemolytically active murine fourth component of complement in transfected L cells.
abstract: The S region of the murine major histocompatibility complex contains two related genes (C4-X and C4-Y), one of which encodes the fourth component of complement (C4). We have introduced cloned C4-X and C4-Y genes into L cells. C4-X transfectants contained no detectable C4-related RNA, whereas C4-Y transfectants contained large amounts of C4-related RNA. Culture supernatants of C4-Y transfectants contained processed C4 which was indistinguishable from macrophage-derived C4. The L-cell-derived C4 restored hemolytic activity to C4-deficient serum, served as a substrate for C1s, and underwent autolytic cleavage suggesting the presence of an intramolecular thiolester bond. These experiments identify C4-Y as the functional C4 gene in H-2d mice and indicate that L cells can process pro-C4 correctly.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003181:Complement C4 / Q000235:genetics* / Q000378:metabolism; D004262:DNA Restriction Enzymes; D005796:Genes; D006461:Hemolysis; D007700:Kinetics; D007739:L Cells / Q000378:metabolism; D008285:Major Histocompatibility Complex; D051379:Mice; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D003181:Complement C4; D004262:DNA Restriction Enzymes