title: P19INK4D links endomitotic arrest and megakaryocyte maturation and is regulated by AML-1.
abstract: The molecular mechanisms that regulate megakaryocyte (MK) ploidization are poorly understood. Using MK differentiation from primary human CD34(+) cells, we observed that p19(INK4D) expression was increased both at the mRNA and protein levels during ploidization. p19(INK4D) knockdown led to a moderate increase (31.7% +/- 5%) in the mean ploidy of MKs suggesting a role of p19(INK4D) in the endomitotic arrest. This increase in ploidy was associated with a decrease in the more mature MK population (CD41(high)CD42(high)) at day 9 of culture, which was related to a delay in differentiation. Inversely, p19(INK4D) overexpression in CD34(+) cells resulted in a decrease in mean ploidy level associated with an increase in CD41 and CD42 expression in each ploidy class. Confirming these in vitro results, bone marrow MKs from p19(INK4D) KO mice exhibited an increase in mean ploidy level from 18.7N (+/- 0.58N) to 52.7N (+/- 12.3N). Chromatin immunoprecipitation assays performed in human MKs revealed that AML-1 binds in vivo the p19(INK4D) promoter. Moreover, AML-1 inhibition led to the p19(INK4D) down-regulation in human MKs. These results may explain the molecular link at the transcriptional level between the arrest of endomitosis and the acceleration of MK differentiation.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U790, Villejuif, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Gilles
authors.forename: Romain
authors.initials: R
authors.lastname: Guièze
authors.forename: Dominique
authors.initials: D
authors.lastname: Bluteau
authors.forename: Véronique
authors.initials: V
authors.lastname: Cordette-Lagarde
authors.forename: Catherine
authors.initials: C
authors.lastname: Lacout
authors.forename: Rémi
authors.initials: R
authors.lastname: Favier
authors.forename: Fréderic
authors.initials: F
authors.lastname: Larbret
authors.forename: Najet
authors.initials: N
authors.lastname: Debili
authors.forename: William
authors.initials: W
authors.lastname: Vainchenker
authors.forename: Hana
authors.initials: H
authors.lastname: Raslova
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation; D050676:Core Binding Factor Alpha 2 Subunit / Q000378:metabolism*; D050764:Cyclin-Dependent Kinase Inhibitor p19 / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology*; D051379:Mice; D008938:Mitosis; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism; D011003:Ploidies; D011401:Promoter Regions, Genetic / Q000235:genetics
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D050764:Cyclin-Dependent Kinase Inhibitor p19; D019038:Platelet Glycoprotein GPIb-IX Complex; D040201:Platelet Membrane Glycoprotein IIb