title: Id2 reverses cell cycle arrest induced by {gamma}-irradiation in human HaCaT keratinocytes.
abstract: Id2 plays a key role in epithelial cells, regulating differentiation, the cell cycle, and proliferation. Because human skin constantly renews itself and is the first target of irradiation, it is of primary interest to evaluate whether such a gene may be regulated in keratinocytes exposed to ionizing radiation. We show here that Id2 is induced in response to gamma-irradiation and have investigated the consequence of this regulation on cell fate. Using RNA interference, we observed that Id2 extinction significantly reduces cell growth in human keratinocytes through the control of the G(1)-S transition of the cell cycle. We have investigated whether the impact of Id2 on the cell cycle may have a physiological role on the cell's ability to cope with radiative stress. Indeed, when Id2 is down-regulated through interfering RNA, cells are more sensitive to irradiation. Conversely, when Id2 is overexpressed, this somehow protects the cell. We propose that Id2 favors reentering the cell cycle after radiation-induced cell cycle arrest to permit the recovery of keratinocytes exposed to ionizing radiation.
authors.affiliation: Service de Génomique Fonctionnelle, Commissariat à l'Energie Atomique-Evry, 2 rue Gaston Crémieux, CP22, 91057 Evry, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Baghdoyan
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lamartine
authors.forename: David
authors.initials: D
authors.lastname: Castel
authors.forename: Amandine
authors.initials: A
authors.lastname: Pitaval
authors.forename: Yoann
authors.initials: Y
authors.lastname: Roupioz
authors.forename: Noreli
authors.initials: N
authors.lastname: Franco
authors.forename: Mariela
authors.initials: M
authors.lastname: Duarte
authors.forename: Michèle T
authors.initials: MT
authors.lastname: Martin
authors.forename: Xavier
authors.initials: X
authors.lastname: Gidrol
mesh_terms: D002453:Cell Cycle / Q000502:physiology / Q000528:radiation effects*; D049109:Cell Proliferation / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005720:Gamma Rays; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; D012097:Repressor Proteins; D014157:Transcription Factors