Structure of the murine mb-1 gene encoding a putative sIgM-associated molecule.
Genomic DNA clones containing the B cell-specific murine mb-1 gene were isolated and a 5.6-kb BamH I fragment was characterized. It is 5629 bp long and contains five exons: an exon containing the 5' untranslated and the coding sequence of the signal peptide, an exon of 294 bp, which contains most of the extracellular sequence of the MB-1 protein, a 119-bp long exon coding mainly for the transmembrane portion, and two exons of 69 bp and 427 bp encoding the cytoplasmic domain and the 3'-untranslated region, respectively. The mb-1 gene does not contain a "TATA box" found in many eukaryotic promoters. The 5'-flanking region has sequence stretches homologous to IgVH 5'-promoter regions and a bcl 2 intron sequence. It contains the decanucleotide sequence (ATGGCAAATA) almost identical to the octamer motif of IgVH promoters. A B cell-specific DNase I-hypersensitive site was found in the 3'-flanking region indicating that this region might be involved in B cell-specific expression of mb-1. Southern blot analysis of genomic liver DNA with the cloned mb-1 cDNA suggests the existence of another mb-1-related gene segment.
Kashiwamura
S
S
Department of Immunology, Saga Medical School, Japan.
Koyama
T
T
Matsuo
T
T
Steinmetz
M
M
Kimoto
M
M
Sakaguchi
N
N
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D001483:Base Sequence; D015139:Blotting, Southern; D051925:CD79 Antigens; D003850:Deoxyribonuclease I / Q000494:pharmacology; D005796:Genes; D007075:Immunoglobulin M / Q000378:metabolism*; D007438:Introns; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D014158:Transcription, Genetic
D015703:Antigens, CD; D051925:CD79 Antigens; C497882:Cd79a protein, mouse; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D003850:Deoxyribonuclease I