Reactivation by exon shuffling of a conserved HLA-DR3-like pseudogene segment in a New World primate species.
The common marmoset (Callithrix jacchus), a New World monkey species with a limited MHC class II repertoire, is highly susceptible to certain bacterial infections. Genomic analysis of exon 2 sequences documented the existence of only one DRB region configuration harboring three loci. Two of these loci display moderate levels of allelic polymorphism, whereas the -DRB*W12 gene appears to be monomorphic. This study shows that only the Caja-DRB*W16 and -DRB*W12 loci produce functional transcripts. The Caja-DRB1*03 locus is occupied by a pseudogene, given that most of the transcripts, if detected at all, show imperfections and are present at low levels. Moreover, two hybrid transcripts were identified that feature the evolutionarily conserved peptide-binding motif characteristic for the Caja-DRB1*03 gene. Thus, the severely reduced MHC class II repertoire in common marmosets has been expanded by reactivation of a pseudogene segment as a result of exon shuffling.
Department of Comparative Genetics and Refinement, Biomedical Primate Research Centre, P.O. Box 3306, 2280 GH, Rijswijk, The Netherlands.
Gaby G M
GG
Doxiadis
Marit K H
MK
van der Wiel
Herbert P M
HP
Brok
Natasja G
NG
de Groot
Nel
N
Otting
Bert A
BA
't Hart
Jon J
JJ
van Rood
Ronald E
RE
Bontrop
D000595:Amino Acid Sequence; D000818:Animals; D005091:Exons; D015803:HLA-DR3 Antigen / Q000235:genetics*; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D008969:Molecular Sequence Data; D011323:Primates / Q000235:genetics* / Q000276:immunology*; D011544:Pseudogenes; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D015803:HLA-DR3 Antigen; D000949:Histocompatibility Antigens Class II