title: EKLF-driven PIT1 expression is critical for mouse erythroid maturation in vivo and in vitro.
abstract: The PIT1/SLC20A1 protein, a well-described sodium/phosphate cotransporter and retrovirus receptor, has been identified recently as a modular of proliferation and apoptosis in vitro. The targeted deletion of the PIT1 gene in mice revealed a lethal phenotype due to severe anemia attributed to defects in liver development. However, the presence of immature erythroid cells associated with impaired maturation of the globin switch led us to investigate the role of PIT1 in hematopoietic development. In the present study, specific deletion of PIT1 in the hematopoietic system and fetal liver transplantation experiments demonstrated that anemia was associated with an erythroid cell- autonomous defect. Moreover, anemia was not due to RBC destruction but rather to maturation defects. Because Erythroid Krüppel-like Factor (EKLF)-knockout mice showed similar maturation defects, we investigated the functional link between PIT1 and EKLF. We demonstrated that EKLF increases PIT1 expression during RBC maturation by binding to its promoter in vivo and that shRNA-driven depletion of either PIT1 or EKLF impairs erythroid maturation of G1E cells in vitro, whereas reexpression of PIT1 in EKLF-depleted G1E cells partially restores erythroid maturation. This is the first demonstration of a physiologic involvement of PIT1 in erythroid maturation in vivo.
authors.affiliation: Inserm U845, Paris, France. anne.forand@inserm.fr
authors.forename: Anne
authors.initials: A
authors.lastname: Forand
authors.forename: Laurent
authors.initials: L
authors.lastname: Beck
authors.forename: Christine
authors.initials: C
authors.lastname: Leroy
authors.forename: Alice
authors.initials: A
authors.lastname: Rousseau
authors.forename: Valérie
authors.initials: V
authors.lastname: Boitez
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cohen
authors.forename: Geneviève
authors.initials: G
authors.lastname: Courtois
authors.forename: Olivier
authors.initials: O
authors.lastname: Hermine
authors.forename: Gérard
authors.initials: G
authors.lastname: Friedlander
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D003114:Colony-Forming Units Assay; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism*; D004920:Erythropoiesis / Q000235:genetics; D017353:Gene Deletion; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism*; D008099:Liver / Q000196:embryology / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010641:Phenotype; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D050817:Transcription Factor Pit-1 / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D051741:Kruppel-Like Transcription Factors; D050817:Transcription Factor Pit-1; C080774:erythroid Kruppel-like factor