Analysis of genomic and expressed major histocompatibilty class Ia and class II genes in a hexaploid Lake Tana “large” barb individual (Barbus intermedius).

C. P. Kruiswijk, T. T. Hermsen, K. Fujiki, B. Dixon, H. F. J. Savelkoul, Rene Josephus Maria Stet

    Research output: Contribution to journalArticle

    38 Citations (Scopus)

    Abstract

    Expression of too many co-dominant major histocompatibility complex (MHC) alleles is thought to be detrimental to proper functioning of the immune system. Polyploidy of the genome will increase the number of expressed MHC genes unless they are prone to a silencing mechanism. In polyploid Xenopus species, the number of MHC class I and II genes has been physically reduced, as it does not increase with higher ploidy genomes. In the zebrafish some class IIB loci have been silenced, as only two genomically bona fide loci, DAA/DAB and DEA/DEB, have been described. Earlier studies indicated a reduction in the number of genomic and expressed class II MHC genes in a hexaploid African 'large' barb. This prompted us to study the number of MHC genes present in the genome of an African 'large' barb individual (Barbus intermedius) in relation to those expressed, adopting the following strategy. Full-length cDNA sequences were generated from mRNA and compared with partial genomic class Ia and II sequences generated by PCR using the same primer set. In addition, we performed Southern hybridizations to obtain a verification of the number of class I and IIB genes. Our study revealed three beta(2)-microglobulin, five class Ia, four class IIA, and four class IIB genes at the genomic level, which were shown to be expressed in the hexaploid barb individual. The class Ia and class II data indicate that the ploidy status does not correlate with the presence and expression of these MHC genes.

    Original languageEnglish
    Pages (from-to)770-781
    Number of pages11
    JournalImmunogenetics
    Volume55
    DOIs
    Publication statusPublished - 2004

    Keywords

    • MHC class I
    • MHC class II
    • gene silencing
    • ploidy
    • African 'large' barb
    • MHC CLASS-I
    • COMPLEX CLASS-I
    • CARP CYPRINUS-CARPIO
    • BETA-2-MICROGLOBULIN GENE
    • RAINBOW-TROUT
    • DANIO-RERIO
    • BETA(2)-MICROGLOBULIN
    • FISH
    • EVOLUTION
    • ZEBRAFISH

    Cite this