Organization of the Equine Immunoglobulin Heavy Chain Constant Region Genes; III.Alignment of cN, cβ, cε and cα Genes

Previous restriction analysis of cloned equine DNA and genomic DNA of equine peripheral blood mononuclear cells had indicated the existence of one Cε, one cα and up to six cγ genes in the haploid equine genome.The cε and cα genes have been aligned on a 30 kb DNA fragment in the order 5' cε-cα 3'.Here we describe the alignment of the equine cp and cy genes by deletion analysis of one IgM, four IgG and two, equine light chain expressing heterohybridomas.This analysis establishes the existence of six cγ genes per haploid genome.The genomic alignment of the CH-genes is 5' cμ // cγ1 // cγ2 // cγ3 // cγ4 // cγ5 // cγ6 // cE -cα 3', naming the cγ genes according to their position relative to cp..For three of the cγ genes the corresponding IgG isotypes could be identified as IgGa for cγ1, IgG(T) for cγ3 and IgGb for cγ4.