title: Expression of tal-1 and GATA-binding proteins during human hematopoiesis.
abstract: Tal-1 rearrangements are associated with nearly 30% of human T acute lymphoblastic leukemia. Tal-1 gene encodes a putative transcription factor with a basic helix-loop-helix domain and is known to be predominantly expressed in hematopoietic cells. We investigated the pattern of tal-1 expression in purified human hematopoietic cells by in situ hybridization and reverse transcriptase polymerase chain reaction analysis. Both methods demonstrated that the tal-1 gene is expressed in megakaryocytes and erythroblasts as well as in basophilic granulocytes. In addition, our results indicate that the tal-1 1A promoter, which contains two consensus GATA-binding sites, is active mainly in these lineages. Because the GATA-1 gene is known to transactivate several genes specific for the erythroid, megakaryocytic, and mastocytic/basophilic lineages, we studied GATA-1 expression in these purified hematopoietic cells. We found that GATA-1 and tal-1 genes are coexpressed in these three lineages. Remarkably, the expression of both genes is downmodulated during erythroid and megakaryocytic terminal maturation. In immature hematopoietic cells, tal-1 and GATA-1 genes are coexpressed in committed progenitors cells (CD34+/CD38(2+)), whereas they are not detectable in the most primitive cells (CD34(2+)/CD38-). In contrast, GATA-2 is strongly expressed in both most primitive and committed progenitors cells, whereas GATA-3 is mostly detected in most primitive ones. Altogether our results strongly suggest that GATA-1 modulates the transcription of tal-1 during the differentiation of the erythroid, megakaryocytic, and basosophilic lineages.
authors.affiliation: INSERM 91, Hôpital Henri Mondor, Créteil, France.
authors.forename: M A
authors.initials: MA
authors.lastname: Mouthon
authors.forename: O
authors.initials: O
authors.lastname: Bernard
authors.forename: M T
authors.initials: MT
authors.lastname: Mitjavila
authors.forename: P H
authors.initials: PH
authors.lastname: Romeo
authors.forename: W
authors.initials: W
authors.lastname: Vainchenker
authors.forename: D
authors.initials: D
authors.lastname: Mathieu-Mahul
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D001792:Blood Platelets / Q000502:physiology*; D001853:Bone Marrow / Q000502:physiology; D002460:Cell Line; D002648:Child; D004268:DNA-Binding Proteins / Q000235:genetics*; D050981:Erythroid-Specific DNA-Binding Factors; D005091:Exons; D050982:GATA1 Transcription Factor; D015321:Gene Rearrangement; D006410:Hematopoiesis / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D007938:Leukemia / Q000097:blood / Q000235:genetics*; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000097:blood / Q000235:genetics*; D008533:Megakaryocytes / Q000166:cytology / Q000502:physiology; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D013950:Thymus Gland / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D009838:Oligodeoxyribonucleotides; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C494688:GATA1 protein, human; C067143:TAL1 protein, human