title: Megakaryocyte polyploidization is associated with a functional gene amplification.
abstract: It is believed that polyploidy induces an orchestrated increase in gene expression. To know whether all alleles remain functional during megakaryocyte polyploidization, we used a well-established fluorescence in situ hybridization technique which allows one to simultaneously detect pre-mRNAs and assess ploidy level in a single cell. All alleles of GPIIb, GPIIIa, VWF, beta-actin, hsp70, c-mpl, Fli-1, and FOG-1 genes are transcriptionally active in megakaryocytes from 4N to 32N. All X chromosomes in male cells are transcriptionally active but only half of them are transcriptionally active in female megakaryocytes, as revealed by the transcriptional activity of the GATA-1 gene. Nuclear untranslated XIST RNA accumulates on the inactivated X chromosomes, indicating that they are subjected to a normal inactivation process. Altogether, our results demonstrate that megakaryocyte polyploidization results in a functional gene amplification whose likely function is an increase in protein synthesis parallel with cell enlargement.
authors.affiliation: INSERM U362, and Centre National de la Recherche Scientifique (CNRS) UMR 1599, Institut Gustave Roussy, Villejuif, France.
authors.forename: Hana
authors.initials: H
authors.lastname: Raslova
authors.forename: Lydia
authors.initials: L
authors.lastname: Roy
authors.forename: Claire
authors.initials: C
authors.lastname: Vourc'h
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Le Couedic
authors.forename: Olivier
authors.initials: O
authors.lastname: Brison
authors.forename: Didier
authors.initials: D
authors.lastname: Metivier
authors.forename: Jean
authors.initials: J
authors.lastname: Feunteun
authors.forename: Guido
authors.initials: G
authors.lastname: Kroemer
authors.forename: Najet
authors.initials: N
authors.lastname: Debili
authors.forename: William
authors.initials: W
authors.lastname: Vainchenker
mesh_terms: D000483:Alleles; D002454:Cell Differentiation / Q000235:genetics; D041321:Chromosomes, Human, X; D005260:Female; D005784:Gene Amplification; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism*; D015539:Platelet Activation / Q000235:genetics; D011123:Polyploidy; D015138:RNA, Nuclear / Q000032:analysis; D014158:Transcription, Genetic
chemical_list: D015138:RNA, Nuclear