A second TCRδ locus in Galliformes uses antibody-like V domains: insight into the evolution of TCRδ and TCRμ genes in tetrapods

Analyses of the available avian genomes revealed the presence of a second TCRδ locus in the Galliformes. This second TCRδ locus is nonsyntenic to the conventional TCRα/δ and is unusual in that the V genes are more related to IgH V genes (VH) than to TCR V genes. The second TCRδ is not found in anoth...

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Bibliographic Details
Published in:The Journal of immunology (1950) 2012-04, Vol.188 (8), p.3912-3919
Main Authors: Parra, Zuly E, Mitchell, Kevin, Dalloul, Rami A, Miller, Robert D
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Evolution, Molecular
Galliformes
Galliformes - genetics
Gene Duplication
Genes, T-Cell Receptor
Genes, T-Cell Receptor delta
Genetic Loci
Genome
Genomics
Molecular Sequence Data
Passeriformes
Passeriformes - genetics
Phylogeny
Sequence Alignment
Taeniopygia guttata
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Summary:Analyses of the available avian genomes revealed the presence of a second TCRδ locus in the Galliformes. This second TCRδ locus is nonsyntenic to the conventional TCRα/δ and is unusual in that the V genes are more related to IgH V genes (VH) than to TCR V genes. The second TCRδ is not found in another avian lineage, the passerine zebra finch. Rather the finch's conventional TCRα/δ locus contains VH genes that are expressed with the conventional Cδ gene, similar to what has been found in amphibians. A comparison between Galliformes and Passeriformes genomic organization suggests an origin of the second TCRδ in the former lineage involving gene duplication. Expression of these atypical TCRδ transcripts with a VH domain paired with Cδ was found in lymphoid tissues of both avian lineages. The configuration of the second TCRδ in chicken and turkey is reminiscent of the TCRδ duplication that is present in nonplacental mammals and provides insight into the origin of the uniquely mammalian TCRμ locus.
ISSN:0022-1767
1550-6606
DOI:10.4049/jimmunol.1103521