Human recombination activating gene-1 in leukemia/lymphoma cells: expression depends on stage of lymphoid differentiation defined by phenotype and genotype.
The recombination activating gene, RAG-1, which is supposed to encode a molecule regulating V(D)J recombination, has been isolated. In the current study, the distribution of RAG-1 expression in human neoplastic hematopoietic cells was compared with the phenotypic and genotypic status of differentiation. Thirty-one hematopoietic cell lines (16 B-lineage, 9 T-lineage, 2 Hodgkin's disease, and 4 nonlymphoid cell lines) were investigated for the expression of human RAG-1 using the reverse-transcriptase polymerase chain reaction (RT-PCR). RAG-1 was not expressed in nonlymphoid, Hodgkin's disease, or mature-stage lymphoid cell lines, but was present in some acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma (LBL) cell lines. The investigation was extended to 45 cases of fresh ALL/LBL cells. The patterns of RAG-1 expression found in the cell lines and fresh ALL/LBL cells were similar. In B-lineage cells, the product of RAG-1 RT-PCR was detected in CD19+ CD10- CD20- CD5- stage (stage II, Nadler's classification) and was at the highest level in CD19+ CD10+ CD20- CD5- stage (stage III), but was absent or limited in CD19+ CD10+ CD20-+ CD5- (stage IV) or CD19+ CD10+ (or CD10-) CD5+. In stage II, monoclonal gene rearrangements of only the immunoglobulin heavy chain (IgH) were found, whereas monoclonal gene rearrangements of both IgH and T-cell receptor (TCR)-beta chain were frequently noted in stages III and IV. The expression of CD20 or CD5 antigen apparently correlated with the decline of RAG-1 expression. In T-lineage cells, RAG-1 was highly expressed in CD3- CD4+ CD8+/CD3+ CD4+ CD8+ thymic stages, but was negative or only weakly expressed in the CD3- CD4- CD8- prothymic or early thymic stage, in which the TCR-beta gene was often germline, or the CD3+ CD4+ CD8- mature thymic stage. The relative levels of RAG-1 mRNA give an additional delineating frame to the schemes of lymphoid differentiation based on phenotypic and genotypic status. RAG-1 is exhibited by cells of the thymic stage capable of synthesizing TCR or expressing it on the cell surface. The weak or absent expression of RAG-1 in the prothymic or early thymic stage suggests that the contribution of RAG-1 to the gene rearrangement may differ quantitatively between TCR-delta/TCR-gamma and TCR-beta.(ABSTRACT TRUNCATED AT 400 WORDS)
Department of Laboratory Medicine, Kobe University School of Medicine, Japan.
N
N
Yoneda
E
E
Tatsumi
S
S
Kawano
Y
Y
Matsuo
J
J
Minowada
N
N
Yamaguchi
D001483:Base Sequence; D002454:Cell Differentiation; D004253:DNA Nucleotidylexotransferase / Q000235:genetics; D015870:Gene Expression; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D018398:Homeodomain Proteins; D006801:Humans; D016130:Immunophenotyping; D066298:In Vitro Techniques; D007938:Leukemia / Q000235:genetics* / Q000473:pathology; D008223:Lymphoma / Q000235:genetics* / Q000473:pathology; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics*; D014407:Tumor Cells, Cultured
D018398:Homeodomain Proteins; D009838:Oligodeoxyribonucleotides; D011506:Proteins; C064658:RAG-1 protein; D004253:DNA Nucleotidylexotransferase