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Mapping of the chicken immunoglobulin heavy‐chain constant region gene locus reveals an inverted α gene upstream of a condensed υ gene
Author(s) -
Zhao Y.,
Rabbani H.,
Shimizu A.,
Hammarström L.
Publication year - 2000
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.2000.00106.x
Subject(s) - exon , gene , locus (genetics) , biology , genetics , intron , microbiology and biotechnology , immunoglobulin heavy chain , genomic dna , alpha chain
Summary Chicken antibodies are increasingly being used as diagnostic and therapeutic tools. As only the genomic organization of the µ encoding gene was previously known, we analysed the chicken immunoglobulin Y (IgY) and IgA (υ and α chain) immunoglobulin heavy‐chain constant region (IGHC) genes and the organization of the chicken IGHC locus. The α gene is encoded by four separate exons, whereas, surprisingly, there is no intervening DNA sequence between the CH1 and CH2 domains of the IgY heavy chain, which is thus encoded by three exons separated by two introns. DNA sequence analysis shows that the exon boundaries of the chicken IGHC genes are not consistent with published domain borders. Furthermore, differences in DNA sequence confirm the existence of IgY, IgA and IgM allotypes in chickens. Finally, our results show that the IGHC genes of chicken (IgY, IgA and IgM) are all colocated on chromosome E18C15W15, where the α gene is located upstream of the υ gene in an inverted transcriptional orientation. The distances between the µ and α genes and the α and υ genes are about 18 and 15 kilobases, respectively, and thus, the size of the whole chicken IGHC locus is approximately 67 kilobases.