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Nonclassical MHC class Ib (class Ib) genes are heterogeneous genes encoding molecules that are structurally similar to classical MHC class Ia molecules but with limited tissue distribution and polymorphism. Mammalian class Ib genes have diverse and often uncharacterized functions, and because of their rapid rate of evolution, class Ib phylogeny is difficult to establish. We have conducted an extensive genomic, molecular, and phylogenetic characterization of class Ib genes in two Xenopodinae amphibian species of different genera that diverged from a common ancestor as long ago as primates and rodents (∼65 million years). In contrast with the unsteadiness of mammalian class Ib genes, our results reveal an unusual degree of conservation of most Xenopodinae class Ib gene lineages, including a novel monogenic lineage represented by the divergent Xenopus laevis XNC10 gene and its unequivocal Silurana (Xenopus) tropicalis orthologue, SNC10. The preferential expression of this gene lineage by thymocytes themselves from the onset of thymic organogenesis is consistent with a specialized role of class Ib in early T cell development and suggests such a function is conserved in all tetrapods.
Adams,
Species-specific evolution of MHC class I genes in the higher primates.
2001, Pubmed
Adams,
Species-specific evolution of MHC class I genes in the higher primates.
2001,
Pubmed
Anderson,
A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders.
2008,
Pubmed
Anderson,
Projection of an immunological self shadow within the thymus by the aire protein.
2002,
Pubmed
Bahram,
MIC genes: from genetics to biology.
2000,
Pubmed
Bendelac,
The biology of NKT cells.
2007,
Pubmed
Berg,
Signalling through TEC kinases regulates conventional versus innate CD8(+) T-cell development.
2007,
Pubmed
Braud,
Functions of nonclassical MHC and non-MHC-encoded class I molecules.
1999,
Pubmed
Cadavid,
Evolutionary instability of the major histocompatibility complex class I loci in New World primates.
1997,
Pubmed
Cherry,
Comparisons of frogs, humans, and chimpanzees.
1979,
Pubmed
Cherty,
Frog perspective on the morphological difference between humans and chimpanzees.
1978,
Pubmed
Evans,
A mitochondrial DNA phylogeny of African clawed frogs: phylogeography and implications for polyploid evolution.
2004,
Pubmed
,
Xenbase
Evans,
Genome evolution and speciation genetics of clawed frogs (Xenopus and Silurana).
2008,
Pubmed
,
Xenbase
Flajnik,
The major histocompatibility complex of frogs.
1990,
Pubmed
Flajnik,
A novel type of class I gene organization in vertebrates: a large family of non-MHC-linked class I genes is expressed at the RNA level in the amphibian Xenopus.
1993,
Pubmed
,
Xenbase
Gleimer,
Stress management: MHC class I and class I-like molecules as reporters of cellular stress.
2003,
Pubmed
Gomes,
Non-classical major histocompatibility complex proteins as determinants of tumour immunosurveillance.
2007,
Pubmed
Goyos,
Novel nonclassical MHC class Ib genes associated with CD8 T cell development and thymic tumors.
2009,
Pubmed
,
Xenbase
Hellsten,
The genome of the Western clawed frog Xenopus tropicalis.
2010,
Pubmed
,
Xenbase
Houlden,
Evolution of MHC class I loci in marsupials: characterization of sequences from koala (Phascolarctos cinereus).
1996,
Pubmed
Howcroft,
Expression of nonclassical MHC class Ib genes: comparison of regulatory elements.
2003,
Pubmed
Hughes,
Evolution of duplicate genes in a tetraploid animal, Xenopus laevis.
1993,
Pubmed
,
Xenbase
Kasahara,
Evolution of the major histocompatibility complex: a current overview.
1995,
Pubmed
Koller,
Cloning and complete sequence of an HLA-A2 gene: analysis of two HLA-A alleles at the nucleotide level.
1985,
Pubmed
Koonin,
Orthologs, paralogs, and evolutionary genomics.
2005,
Pubmed
Ladi,
Thymic microenvironments for T cell differentiation and selection.
2006,
Pubmed
Madden,
The structure of HLA-B27 reveals nonamer self-peptides bound in an extended conformation.
1991,
Pubmed
Nei,
Concerted and birth-and-death evolution of multigene families.
2005,
Pubmed
Nei,
Evolution by the birth-and-death process in multigene families of the vertebrate immune system.
1997,
Pubmed
Ohta,
Ancestral organization of the MHC revealed in the amphibian Xenopus.
2006,
Pubmed
,
Xenbase
Robert,
Comparative and developmental study of the immune system in Xenopus.
2009,
Pubmed
,
Xenbase
Rodgers,
MHC class Ib molecules bridge innate and acquired immunity.
2005,
Pubmed
Roelants,
Global patterns of diversification in the history of modern amphibians.
2007,
Pubmed
Saitou,
The neighbor-joining method: a new method for reconstructing phylogenetic trees.
1987,
Pubmed
Salter-Cid,
Expression of MHC class Ia and class Ib during ontogeny: high expression in epithelia and coregulation of class Ia and lmp7 genes.
1998,
Pubmed
,
Xenbase
Saltis,
Evolutionarily conserved and divergent regions of the autoimmune regulator (Aire) gene: a comparative analysis.
2008,
Pubmed
,
Xenbase
Saper,
Refined structure of the human histocompatibility antigen HLA-A2 at 2.6 A resolution.
1991,
Pubmed
Shawar,
Antigen presentation by major histocompatibility complex class I-B molecules.
1994,
Pubmed
Shum,
Isolation of a classical MHC class I cDNA from an amphibian. Evidence for only one class I locus in the Xenopus MHC.
1993,
Pubmed
,
Xenbase
Sullivan,
A structural perspective on MHC class Ib molecules in adaptive immunity.
2006,
Pubmed
Urdahl,
Positive selection of MHC class Ib-restricted CD8(+) T cells on hematopoietic cells.
2002,
Pubmed
Watkins,
Evolution of the MHC class I genes of a New World primate from ancestral homologues of human non-classical genes.
1990,
Pubmed
Wong,
A simplified and improved method for the efficient double-stranded sequencing of mini-prep plasmid DNA.
1990,
Pubmed
