The most primitive vertebrates with jaws possess highly polymorphic MHC class I genes comparable to those of humans.
We report the isolation and extensive analysis of highly polymorphic MHC class I genes from sharks (Triakis scyllia), which belong to the most primitive vertebrate group with jaws, the cartilaginous fish. Predicted complete peptide-binding domains showed retention of the critical amino acid residues that would interact with antigenic peptide termini and revealed extensive allelic polymorphisms comparable to those of classic human MHC class I molecules. Mosaic structures were apparent in these domains, suggesting recombinational mechanisms to create allelic diversity. The present study demonstrates the establishment of the basic strategy for antigen-presentation employed by MHC class I molecules and documents complete divergence of two polymorphic MHC classes at a phylogenetically primitive stage of vertebrate evolution.
Okamura
K
K
Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan.
Ototake
M
M
Nakanishi
T
T
Kurosawa
Y
Y
Hashimoto
K
K
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002874:Chromosome Mapping; D018076:DNA, Complementary; D005805:Genes, MHC Class I; D006801:Humans; D007568:Jaw; D008969:Molecular Sequence Data; D009030:Mosaicism; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012754:Sharks / Q000235:genetics* / Q000276:immunology; D013045:Species Specificity
D018076:DNA, Complementary