Singlet Oxygen-Mediated Oxidation during UVA Radiation Alters the Dynamic of Genomic DNA Replication.
UVA radiation (320-400 nm) is a major environmental agent that can exert its deleterious action on living organisms through absorption of the UVA photons by endogenous or exogenous photosensitizers. This leads to the production of reactive oxygen species (ROS), such as singlet oxygen (1O2) and hydrogen peroxide (H2O2), which in turn can modify reversibly or irreversibly biomolecules, such as lipids, proteins and nucleic acids. We have previously reported that UVA-induced ROS strongly inhibit DNA replication in a dose-dependent manner, but independently of the cell cycle checkpoints activation. Here, we report that the production of 1O2 by UVA radiation leads to a transient inhibition of replication fork velocity, a transient decrease in the dNTP pool, a quickly reversible GSH-dependent oxidation of the RRM1 subunit of ribonucleotide reductase and sustained inhibition of origin firing. The time of recovery post irradiation for each of these events can last from few minutes (reduction of oxidized RRM1) to several hours (replication fork velocity and origin firing). The quenching of 1O2 by sodium azide prevents the delay of DNA replication, the decrease in the dNTP pool and the oxidation of RRM1, while inhibition of Chk1 does not prevent the inhibition of origin firing. Although the molecular mechanism remains elusive, our data demonstrate that the dynamic of replication is altered by UVA photosensitization of vitamins via the production of singlet oxygen.
CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France; Curie Institute, PSL Research University, Orsay, France.
Dany
D
Graindorge
CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France; Curie Institute, PSL Research University, Orsay, France.
Sylvain
S
Martineau
Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Laboratoire de biochimie-toxicologie, Pierre Bénite, France; Laboratoire de chimie analytique, Université Lyon 1, ISPBL, Faculté de pharmacie, Lyon, France.
Christelle
C
Machon
Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), Nancy, France; CNRS, UMR7274, Nancy, France.
Philippe
P
Arnoux
Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Laboratoire de biochimie-toxicologie, Pierre Bénite, France; Laboratoire de Toxicologie, Université Lyon 1, ISPBL, Faculté de pharmacie, Lyon, France.
Jérôme
J
Guitton
CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France; Curie Institute, PSL Research University, Orsay, France.
Stefania
S
Francesconi
Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), Nancy, France; CNRS, UMR7274, Nancy, France.
Céline
C
Frochot
CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France; Curie Institute, PSL Research University, Orsay, France.
Evelyne
E
Sage
CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France; Curie Institute, PSL Research University, Orsay, France.
Pierre-Marie
PM
Girard
D002460:Cell Line; D004247:DNA / Q000378:metabolism / Q000528:radiation effects*; D004261:DNA Replication / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D026082:Singlet Oxygen / Q000378:metabolism*; D014466:Ultraviolet Rays
D017382:Reactive Oxygen Species; D026082:Singlet Oxygen; D004247:DNA; D006861:Hydrogen Peroxide