Hildebrand W H, Horton R M, Pease L R, Martinko J M
Department of Microbiology, Southern Illinois University, Carbondale 62901.
Mol Immunol. 1992 Jan;29(1):61-9. doi: 10.1016/0161-5890(92)90157-s.
The nucleotide sequence of the standard H-2Df allele and the spontaneous in vivo H-2Dfm2 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-2f and mutant B10.M-H-2fm2/Mob mice. A partial Df genomic clone and direct Df and Dfm2 mRNA sequence analysis confirmed the authenticity of the cDNA clones. Interestingly, H-2Df contains a proline in the alpha-helix of the alpha 1 domain at amino acid position 62; no other known class I molecule has a proline at this position. The H-2Dfm2 mutation, however, replaces this unique proline in Df 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-2Dfm2 mutation is flanked by a stretch of 47 nucleotide bases with an identical counterpart in H-2Kf, a finding consistent with a recombinatorial event between H-2Kf and H-2Df.
本文报道了标准H-2Df等位基因的核苷酸序列以及体内自发的H-2Dfm2突变。利用小鼠MHC I类H-2D区域基因5'和3'非翻译区的位点特异性序列设计引物，用于从标准B10.M/Sn H-2f和突变体B10.M-H-2fm2/Mob小鼠中特异性扩增和克隆H-2D区域cDNA。部分Df基因组克隆以及直接的Df和Dfm2 mRNA序列分析证实了cDNA克隆的真实性。有趣的是，H-2Df在α1结构域的α螺旋中第62位氨基酸处含有一个脯氨酸；没有其他已知的I类分子在该位置有脯氨酸。然而，H-2Dfm2突变将Df中这个独特的脯氨酸替换为第62位的H-2和HLA共有精氨酸。虽然不能排除点突变，但H-2Dfm2突变中的单核苷酸变化两侧有一段47个核苷酸碱基的序列，在H-2Kf中有相同的对应序列，这一发现与H-2Kf和H-2Df之间的重组事件一致。
