Nucleotide sequence analysis of H-2D^f and the spontaneous in vivoH-2D^fm2 mutation

The nucleotide sequence of the standard H-2D^f allele and the spontaneous in vivoH-2D^fm2 mutation are reported here. Locus-specific sequences in the 5' and 3' untranslated regions of the mouse MHC class I H-2D-region genes were used to design primers for the specific amplification and cloning of H-2D-region cDNA from standard B10.M/Sn H-2^f and mutant BIO.M-H-2^fm2/Mob mice. A partial D^f genomic clone and direct D^f and D^fm2 mRNA sequence analysis confirmed the authenticity of the cDNA clones. Interestingly, H-2D^f contains a proline in the α-helix of the α 1 domain at amino acid position 62; no other known class I molecule has a proline at this position. The H-2D^fm2 mutation, however, replaces this unique proline in D^f with the H-2 and HLA consensus arginine at position 62. Although a point mutation cannot be ruled out, the single nucleotide change in the H-2D^fm2 mutation is flanked by a stretch of 47 nucleotide bases with an identical counterpart in H-2K^f, a finding consistent with a recombinatorial event between H-2K^f and H-2D^f.