title: Loss of Hmga1 gene function affects embryonic stem cell lympho-hematopoietic differentiation.
abstract: By interacting with transcription machinery, high-mobility group A 1 (HMGA1) proteins alter the chromatin structure and thereby regulate the transcriptional activity of several genes. To assess their role in development, we studied the in vitro differentiation of embryonic stem (ES) cells that bear one or both disrupted Hmga1 alleles. Here, we report that Hmga1 null ES cells generate fewer T-cell precursors than do wild-type ES cells. Indeed, they preferentially differentiate to B cells, probably consequent to decreased interleukin 2 expression and increased interleukin 6 expression. Moreover, a lack of HMGA1 expression induces changes in hemopoietic differentiation, i.e., a reduced monocyte/macrophage population and an increase in megakaryocyte precursor numbers, erythropoiesis, and globin gene expression. Re-expression of the Hmga1 gene in Hmga1 null ES cells restores the wild-type phenotype. The effect on megakaryocyte/erythrocyte lineages seems, at least in part, mediated by the GATA-1 transcription factor, a key regulator of red blood cell differentiation. In fact, we found that Hmga1-/- ES cells overexpress GATA-1 and that HMGA1 proteins directly control GATA-1 transcription. Taken together, these data indicate that HMGA1 proteins play a prime role in lymphohematopoietic differentiation.
authors.affiliation: Dipartimento di Biologia e Patologia Cellulare e Molecolare c/o Centro di Endocrinologia ed Oncologia Sperimentale del CNR, Facoltà di Medicina e Chirurgia, Università degli Studi di Napoli Federico II, via Pansini 5, 80131 Naples, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Battista
authors.forename: Francesca
authors.initials: F
authors.lastname: Pentimalli
authors.forename: Gustavo
authors.initials: G
authors.lastname: Baldassarre
authors.forename: Monica
authors.initials: M
authors.lastname: Fedele
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fidanza
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Croce
authors.forename: Alfredo
authors.initials: A
authors.lastname: Fusco
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D002455:Cell Division; D048429:Cell Size; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004622:Embryo, Mammalian / Q000166:cytology*; D004625:Embryo, Nonmammalian; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis; D018507:Gene Expression Regulation, Developmental; D005914:Globins / Q000096:biosynthesis / Q000235:genetics; D024003:HMGA Proteins / Q000235:genetics / Q000502:physiology*; D006410:Hematopoiesis; D038041:Lymphopoiesis; D008533:Megakaryocytes / Q000502:physiology; D008954:Models, Biological; D022423:Myeloid Cells / Q000502:physiology; D020218:Response Elements; D013234:Stem Cells / Q000166:cytology*; D013601:T-Lymphocytes / Q000276:immunology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D024003:HMGA Proteins; D014157:Transcription Factors; D005914:Globins