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High polymorphism of Mhc‐E locus in non‐human primates: alleles with identical exon 2 and 3 are found in two different species

1997; Wiley; Volume: 49; Issue: 2 Linguagem: Inglês

10.1111/j.1399-0039.1997.tb02730.x

1399-0039

M. Álvarez, Jorge Martı́nez-Laso, Paloma F. Varela, Nieves Díaz-Campos, Eduardo Gómez-Casado, Gilberto Vargas‐Alarcón, Carlos Garcı́a-Torre, A. Amaiz‐Villena,

HIV Research and Treatment

Thirteen Mhc‐E new sequences were found in eight individuals belonging to the Cercopithecinae family, i.e.: Macaca mulatta, Macaca fascicularis and Cercopithecus aethiops when studying E locus polymorphism. No changes were found in the invariant residues which are required for the correct conformation of the peptide presenting region which are conserved in classical Mhc class I molecules from fish and reptiles to humans; however, polymorphism of Mhc‐E alleles is not limited to the three typical hypervariable regions per domain as it is in classical class I alleles. The rate of synonymous and non‐synonymous substitutions in the DNA sequence corresponding to the antigen binding site, compared to the remainder ofexons 2 and 3 shows that the peptide‐binding site is under high evolutionary pressure for stability since only synonymous substitutions have been found to be accepted in apes. Also, a clear example of trans‐species evolution of allelism is found: two identical exon 2 and exon 3 sequences there exist belonging to individuals from different species ( Mamu‐Mhc‐E*0101 and Mafa‐Mhc‐E*04 ). In addition, two Macaca mulatta individuals show an Mhc‐E locus duplication. Finally, phylogenetic tree analysis shows that Mhc class I molecules found in Saguinus oedipus (described as Mhc‐G homologues) are closer to Mhc‐E sequences.