title: Gfi-1B promoter remains associated with active chromatin marks throughout erythroid differentiation of human primary progenitor cells.
abstract: Growth Factor Independent-1B (Gfi-1B) is a transcriptional repressor that plays critical roles in the control of erythropoiesis and megakaryopoiesis. Gfi-1B expression was described to be repressed by an autoregulatory feedback control loop. Here, we show that Gfi-1 transcription is positively regulated early after induction of erythroid differentiation and remains highly active to late erythroblasts. Using chromatin immunoprecipitation assays in CD34+ cells from human cord blood, we found that Gfi-1 and GATA-2 in immature progenitors and then Gfi-1B and GATA-1 in erythroblasts are bound to the Gfi-1B promoter as well as to the promoter of c-myc, a known Gfi-1B target gene. Surprisingly, this Gfi-1/GATA-2-Gfi-1B/GATA-1 switch observed at erythroblast stages is associated to an increase in the Gfi-1B transcription whereas it triggers repression of c-myc transcription. Accordingly, analysis of chromatin modification patterns shows that HDAC, CoREST, and LSD1 are recruited to the c-myc promoter leading to appearance of repressive chromatin marks. In contrast, the Gfi-1B promoter remains associated with a transcriptionally active chromatin configuration as highlighted by an increase in histone H3 acetylation and concomitant release of the LSD1 and CoREST corepressors. The repressive function of Gfi-1B therefore depends on the nature of the proteins recruited to the target gene promoters and on chromatin modifications. We conclude that Gfi-1B behaves as a lineage-affiliated gene with an open chromatin configuration in multipotent progenitors and sustained activation as cells progress throughout erythroid differentiation.
authors.affiliation: Institut Cochin, Université Paris Descartes, Centre National de la Recherche Scientifique (UMR 8104), Paris, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Laurent
authors.forename: Voahangy
authors.initials: V
authors.lastname: Randrianarison-Huetz
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kadri
authors.forename: Paul-Henri
authors.initials: PH
authors.lastname: Roméo
authors.forename: Françoise
authors.initials: F
authors.lastname: Porteu
authors.forename: Dominique
authors.initials: D
authors.lastname: Duménil
mesh_terms: D015153:Blotting, Western; D002454:Cell Differentiation; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D056970:Co-Repressor Proteins; D041905:Erythroid Cells / Q000166:cytology* / Q000378:metabolism*; D050982:GATA1 Transcription Factor / Q000378:metabolism; D050989:GATA2 Transcription Factor / Q000378:metabolism; D005822:Genetic Vectors; D056466:Histone Demethylases / Q000378:metabolism; D006801:Humans; D016086:Lentivirus; D009419:Nerve Tissue Proteins / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
chemical_list: D002843:Chromatin; D056970:Co-Repressor Proteins; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D050989:GATA2 Transcription Factor; C111977:GFI1B protein, human; C489427:MYC protein, human; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; C121019:RCOR1 protein, human; D012097:Repressor Proteins; D056466:Histone Demethylases; C495195:KDM1A protein, human