Primary structure of murine major histocompatibility complex alloantigens. Amino acid sequence of the NH2-terminal ninety-eight residues of the H-2Db glycoprotein

New class II-like genes in the murine MHC

Major histocompatibility complex (MHC) class I molecules present endogenous antigens to CD8+ (cytotoxic) T cells. MHC class II molecules present primarily exogenously derived antigens to CD4+ T cells. Three new genes (Ma, Mb1 and Mb2) located between the Pb and Ob genes of the murine MHC have properties indicating that they are members of the MHC class II gene family, but they are the most divergent class II members so far identified and are almost as closely related in sequence to class I genes as they are to the known class II genes.

Primary structure of the H-2Db alloantigen. II. Additional amino acid sequence information, localization of a third site of glycosylation and evidence for K and D region specific sequences

The complete amino acid sequence of the CNBr fragment comprising residues 229-284 of the murine major histocompatibility complex antigen H-2Db has been determined using radiochemical methodology. The sequence was determined by N-terminal sequence analysis of the intact CNBr fragment and by sequence determinations of peptides derived from this fragment by trypsin and staphylococcal V8 protease cleavage. In addition to the amino acid assignments for H-2Db, it was possible to assign the linkage position of the third N-linked glycosyl unit to the asparagine at residue 256. Additional amino acid sequence assignments have also been made for three other CNBr fragments that span residues 99-138, 139-228, and 308-331 of the H-2Db molecule. The total protein sequence information available (222 of 338 residues) agrees in every comparable position with the protein sequence derived from the cDNA clone (pH203) isolated by Reyes and co-workers (1982b), which strongly suggests that this clone encodes H-2Db. Combination of the protein sequence with that deduced from the cDNA clone provides the complete H-2Db protein sequence. Comparison of this sequence with other available protein sequence information for murine class I molecules has revealed protein sequences that may be unique to either K or D region molecules.

The complete amino acid sequence of the murine transplantation antigen H-2Db as deduced by molecular cloning

A mouse cDNA library derived from the EL4 cell line (b-haplotype) was screened with a probe containing a small part of the H-2Kb coding region. One of the clones isolated, pH203, encodes a protein whose deduced amino acid sequence is identical with the known sequence of H-2Db in 141 of 141 positions available for comparison. The clone, therefore, is believed to code for the H-2Db transplantation antigen. The cDNA insert of pH203 contains the coding region for residues 82 through the carboxy-terminus of H-2Db, and includes 476 nucleotides of the 3'-untranslated sequence. Comparison between the H-2Db cDNA clone and a previously isolated H-2Kb cDNA clone shows homologies of 83% and 91% at the amino acid and nucleotide levels, respectively. Analysis of DNA sequences at the 3'-coding and untranslated regions suggests that the mRNAs of H-2Kb and H-2Db are spliced differently at their 3'-coding ends.

Amino acid sequence of the carboxyl-terminal hydrophilic region of the H-2Kb MHC alloantigen. Completion of the entire primary structure of the H-2Kb molecule

The amino acid sequence of the COOH-terminal hydrophilic region of the H-2Kb histocompatibility antigen was determined. The sequence was completed by analyses of four CNBr fragments obtained from the intact molecule as well as tryptic peptides. This region was composed of 39 amino acid residues with a cluster of basic residues at the NH2 terminus and localized positions 308-346 of the H-2Kb molecule. These sequence data, together with those reported for the NH2-terminal 284 residues [Martinko, J. M., Uehara, H., Ewenstein, B. M., Kindt, T. J., Coligan, J. E., & Nathenson, S. G. (1980) Biochemistry 19, 6188-6193] and for the intramembranous segment [Uehara, H., Coligan, J. E., & Nathenson, S. G. (1981) Biochemistry (preceding paper in this issue)], provided the complete primary structure of the H-2Kb molecule. This is the first histocompatibility antigen for which the entire primary structure is determined.