Selective expression of the murine homologue of the G-protein-coupled receptor BLR1 in B cell differentiation, B cell neoplasia and defined areas of the cerebellum.
The Burkitt's lymphoma receptor 1 (BLR1) identified initially in Burkitt lymphoma cells has been the first member of the superfamily of G-protein-coupled receptors with a lymphocyte specific expression pattern. BLR1 shows significant relationship to receptors for chemokines (IL-8, MIP-1 beta) and neuropeptides. The gene encoding the murine homologue of the human BLR1 receptor was isolated and used to study its tissue-specific expression. Blr-1 consists of two exons encoding a protein of 374 amino acid residues which shows 83% identity with the human homologue. Screening of normal tissues of adult BALB/c mice revealed that blr-1-specific RNA is detected consistently at low levels in secondary lymphatic organs. The blr-1 gene is expressed regularly and strongly in lymphomas of mature B cells but not in plasmacytomas. SCID mice deficient in the development of mature B cells have strongly reduced levels of blr-1-specific RNA in the spleen. Cytokine mediated induction (IL4, IL6) of terminal differentiation of resting B cells towards Ig-secreting plasma cells completely downregulates expression of blr-1. RNA in situ hybridization using brain sections demonstrates blr 1 transcription in the granule and Purkinje cell layer of the cerebellum. The precise delineation of the restricted expression pattern of the blr-1 gene will support the identification of its ligand and may provide a clue to understand how BLR1 exerts its biological function within the immune and nervous system.
Förster
R
R
Max-Delbrück-Centre for Molecular Medicine, Berlin-Buch, Federal Republic of Germany.
Wolf
I
I
Kaiser
E
E
Lipp
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D002454:Cell Differentiation; D002525:Cerebellar Cortex / Q000378:metabolism*; D003001:Cloning, Molecular; D005091:Exons; D019204:GTP-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation; D008221:Lymphoid Tissue / Q000378:metabolism*; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009928:Organ Specificity; D010950:Plasma Cells / Q000378:metabolism; D010954:Plasmacytoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011689:Purkinje Cells / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D054380:Receptors, CXCR5; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000096:biosynthesis* / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016511:Severe Combined Immunodeficiency / Q000378:metabolism; D014407:Tumor Cells, Cultured
C513179:CXCR5 protein, mouse; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D054380:Receptors, CXCR5; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D019204:GTP-Binding Proteins