title: Sequence of gene and cDNA encoding murine major histocompatibility complex class II gene A beta 2.
abstract: The murine major histocompatibility complex is known to express two class II molecules, A and E. They are composed of one alpha- and one beta-polypeptide chain. Recently, we reported the finding of an additional beta-chain second domain exon tentatively designated A beta 2. We describe here the nucleotide sequence of the A beta 2 gene and an A beta 2 cDNA clone. A beta 2 displays the same exon organization as the known expressed beta-chain genes, and the predicted A beta 2 polypeptide shows all the characteristic features of the expressed beta-chains. The predicted A beta 2 polypeptide shows 49-56% amino acid sequence identity to A beta and E beta chains and to the human DP, DQ, and DR beta-chains. These are 63-79% homologous to each other, indicating that A beta 2 is the most divergent member of the beta-chain family. The A beta 2 gene seems to be transcribed in the same types of cells as other class II genes. Detection of incompletely spliced A beta 2 mRNA and the finding of a cDNA clone containing an intron segment suggest that A beta 2 transcripts are processed slowly. Hybridizations with A beta 2 probes to restriction enzyme-digested genomic DNA indicate that the A beta 2 gene displays lower allelic polymorphism than the A beta gene.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant; D006183:H-2 Antigens / Q000235:genetics*; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex; D051379:Mice; D009693:Nucleic Acid Hybridization; D011110:Polymorphism, Genetic; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004274:DNA, Recombinant; D006183:H-2 Antigens; D046911:Macromolecular Substances; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D004247:DNA; D004262:DNA Restriction Enzymes