title: Identification of the size and antigenic determinants of the human C4 gene by a polymerase chain-reaction-based amplification method.
abstract: The human C4 complement components of the C4 locus are encoded by two genes, C4A and C4B, located on chromosome 6p21.3 of the major histocompatibility complex of the human leukocyte antigen class III region. The size difference between the two genes is due to the presence of HERV-K (C4), an endogenous retroviral sequence (6.7 kb long), in intron 9 of the long C4 gene. Whether the C4 is the long (L) or short (S) gene was determined by the Southern blot method, and the antigenic determinants in residues 1,054-1,106 of Rodgers and Chido were generally identified by immunoblot analysis. Herein, we explore a polymerase chain reaction (PCR) amplification method for directly determining the size of C4 loci adjacent to the respective RP1 and RP2 genes and antigenic determinants by DNA sequencing. From the results of this study, we concluded that all of the C4 genes adjacent to the RP1 gene presented the long gene. In addition, 47% of the C4 genes adjacent to the RP2 gene were the short gene and 53% were the long gene. This result was consistent with that of the Southern blot analysis. The PCR method is practical for identifying the C4 genotype and can be used to detect other polymorphisms among variants of C4 genes.
authors.affiliation: Department of Medical Research, Mackay Memorial Hospital, No. 45 Min-Sheng Road, Tanshui, Taipei Co. 251, Taiwan. hhlee@ms1.mmh.org.tw
authors.forename: Hsien-Hsiung
authors.initials: HH
authors.lastname: Lee
authors.forename: Shwu-Fen
authors.initials: SF
authors.lastname: Chang
authors.forename: Yung-Te
authors.initials: YT
authors.lastname: Tseng
authors.forename: Yann-Jinn
authors.initials: YJ
authors.lastname: Lee
mesh_terms: D044466:Asian People; D001483:Base Sequence; D003181:Complement C4 / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D000939:Epitopes / Q000032:analysis*; D005136:Eye Proteins / Q000235:genetics; D019204:GTP-Binding Proteins; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D007438:Introns / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008869:Microtubule-Associated Proteins; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods*; D017422:Sequence Analysis, DNA; D013624:Taiwan; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D003181:Complement C4; D000939:Epitopes; D005136:Eye Proteins; C406149:HERV-K cORF protein, Human endogenous retrovirus K; D007132:Immunoglobulin Isotypes; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; C120042:RP1 protein, human; C072178:RP2 protein, human; D014764:Viral Proteins; D019204:GTP-Binding Proteins