IDENTIFICATION OF A NOVEL, H-2-LIKE GENE BY ANALYSIS OF cDNA CLONES

Abstract

Publisher Summary The classical H-2 transplantation antigens of the mouse are encoded by a family of genes that has been mapped to chromosome 17. As membrane-associated proteins, they are responsible for rapid allograft rejection and are involved in the associative recognition of foreign antigens by cytotoxic τ cells. These H-2 antigens are composed of extracellular, transmembrane, and cytoplasmic domains. A series of H-2 cDNA clones has been isolated by screening a mouse liver library with a human HLA-B cDNA probe. Restriction enzyme mapping, cross-hybridization, and partial DNA sequence analysis have shown extensive similarities among the various clones and a high degree of homology with the available protein sequences. However, extensive differences have been detected in the 3' non-coding region of different clones. These differences have been used to define three distinct classes of cDNA clones and to detect three subclasses of H-2 mRNA in mouse liver. The sequence analysis of one class of H-2 cDNA clones has revealed unusual features within the coding sequence for the transmembrane region of the protein. The nucleotide sequence predicts several charged or polar amino acids in this region that would destroy its hydrophobicity. In addition, a small frameshift deletion results in a termination codon toward the cyptolasmic side of the transmembrane region.