Two highly divergent ancient allelic lineages of the transporter associated with antigen processing (TAP) gene in Xenopus: further evidence for co‐evolution among MHC class I region genes
Open Access
- 1 October 2003
- journal article
- research article
- Published by Wiley in European Journal of Immunology
- Vol. 33 (11), 3017-3027
- https://doi.org/10.1002/eji.200324207
Abstract
In the frog Xenopus, MHC class I antigen presentation and processing genes (the immunoproteasome LMP2 and LMP7 and the transporter TAP1 and TAP2) seemto be closely linked in a primordial organization. Two distinct lineages of class Ia and LMP7 loci were previously identified, thus strongly suggesting co-evolution among ‘class I region’ genes. We now show that the Xenopus MHC ‘class I region’ lies between class II and class III genes and we have isolated two distinct alleles at both the TAP1 and TAP2 loci. The alleles at each locus are remarkably divergent from each other and phylogenetic tree analysis revealed in both cases that they diverged from each other 60–100 million years ago (MYA). For lineage-frequency and linkage analysis, 25 wild-caught X. laevis and 16 X. tropicalis were examined. The two lineages were present in different frequencies for X. laevis and X. tropicalis. Nevertheless, in all cases, the LMP7, TAP1, and TAP2 lineages were found in a set comprising one of the two lineages. Furthermore, like the LMP7 lineages, the TAP lineages were detected in most Xenopus species that diverged from a common ancestor 80–100 MYA, suggesting that the ‘class I region’ biallelic lineages are under balancing selection.Keywords
This publication has 38 references indexed in Scilit:
- Extending the Structure of an ABC Transporter to Atomic Resolution: Modeling and Simulation Studies of MsbABiochemistry, 2003
- Three-dimensional Structure of Transporter Associated with Antigen Processing (TAP) Obtained by Single Particle Image AnalysisJournal of Biological Chemistry, 2001
- Comparative Genomics of the MHCImmunity, 2001
- Why are there two rat TAPs?Immunology Today, 1998
- Co-evolution of rat TAP transporters and MHC class I RT1-A moleculesCurrent Biology, 1998
- Roles for Calreticulin and a Novel Glycoprotein, Tapasin, in the Interaction of MHC Class I Molecules with TAPImmunity, 1996
- A point mutation in the human transporter associated with antigen processing (TAP2) alters the peptide transport specificityEuropean Journal of Immunology, 1996
- The Rat cim Effect: TAP Allele-Dependent Changes in a Class I MHC Anchor Motif and Evidence Against C-Terminal Trimming of Peptides in the ERImmunity, 1996
- Selectivity of MHC-encoded peptide transporters from human, mouse and ratNature, 1994
- Genetics of polyploid XenopusTrends in Genetics, 1986