title: G protein subunit G alpha 16 expression is restricted to progenitor B cells during human B-cell differentiation.
abstract: Recently G alpha 16, a new guanosine triphosphate (GTP) binding protein alpha subunit has been described to be specifically expressed in human hematopoietic cells. Expression of G alpha 16 was observed in human cell lines of myelomonocytic and T-lymphocytic origin, but not in human B-cell lines Raji and IM9. We studied the expression of G alpha 16 in human B cells corresponding to different stages of B-cell differentiation by means of reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The human Burkitt's lymphoma cell lines Raji, Ramos, BJAB, the lymphoblastoid cell line SKW6.4, and the plasmocytoma cell line U266 were devoid of G alpha 16. In contrast, G alpha 16 was detected in the human progenitor B cell lines Reh and Nalm-6. Using the mu+, k- cell line BLIN-1 (pre-B cell phenotype) and its derived subclone 1E8 (surface mu+, k+; B-cell phenotype) G alpha 16 expression was found to disappear on transition from pre-B to B-cell differentiation stage. The analysis of a broad panel of human neoplastic B lymphocytes ranging from progenitor B-acute lymphatic leukemia (pre-pre-B-ALL), common acute leukemias (cALL), pre-B-ALL, mature B-ALL to low grade B-cell lymphoma (chronic lymphocytic leukemia of B-cell type, leukemic centrocytic non-Hodgkins lymphoma [NHL], hairy cell leukemia) showed that G alpha 16 expression is limited to progenitor and pre-B-ALL cells. Therefore, we conclude that within B-cell differentiation, G alpha 16 is expressed solely during early B cell ontogeny and downregulated during differentiation. Thus, G alpha 16 might be an important regulator involved in signaling processes in progenitor B cells.
authors.affiliation: Free University of Berlin, University Medical Center Rudolf Virchow, Robert Rössle Klinik, Department of Internal Medicine, Germany.
authors.forename: M Y
authors.initials: MY
authors.lastname: Mapara
authors.forename: K
authors.initials: K
authors.lastname: Bommert
authors.forename: R C
authors.initials: RC
authors.lastname: Bargou
authors.forename: C
authors.initials: C
authors.lastname: Leng
authors.forename: C
authors.initials: C
authors.lastname: Beck
authors.forename: W D
authors.initials: WD
authors.lastname: Ludwig
authors.forename: P
authors.initials: P
authors.lastname: Gierschik
authors.forename: B
authors.initials: B
authors.lastname: Dörken
mesh_terms: D001402:B-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000235:genetics / Q000473:pathology; D002454:Cell Differentiation; D019204:GTP-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D015973:Gene Expression Regulation, Leukemic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016130:Immunophenotyping; D015448:Leukemia, B-Cell / Q000235:genetics / Q000473:pathology; D007943:Leukemia, Hairy Cell / Q000235:genetics / Q000473:pathology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000473:pathology; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics / Q000473:pathology; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics / Q000473:pathology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D010954:Plasmacytoma / Q000235:genetics / Q000473:pathology; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000473:pathology; D011487:Protein Conformation; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D011947:Receptors, Antigen, B-Cell; D019204:GTP-Binding Proteins