DRAGO (KIAA0247), a New DNA Damage–Responsive, p53-Inducible Gene That Cooperates With p53 as Oncosupprossor
Menée in vitro et in vivo, cette étude met en évidence des mécanismes par lesquels, sous le contrôle du gène p53, le gène DRAGO exerce une fonction de suppresseur de tumeurs
Background : p53 influences genomic stability, apoptosis, autophagy, response to stress, and DNA damage. New p53-target genes could elucidate mechanisms through which p53 controls cell integrity and response to damage. Methods : DRAGO (drug-activated gene overexpressed, KIAA0247) was characterized by bioinformatics methods as well as by real-time polymerase chain reaction, chromatin immunoprecipitation and luciferase assays, time-lapse microscopy, and cell viability assays. Transgenic mice (94 p53−/− and 107 p53+/− mice on a C57BL/6J background) were used to assess DRAGO activity in vivo. Survival analyses were performed using Kaplan–Meier curves and the Mantel–Haenszel test. All statistical tests were two-sided. Results : We identified DRAGO as a new p53-responsive gene induced upon treatment with DNA-damaging agents. DRAGO is highly conserved, and its ectopic overexpression resulted in growth suppression and cell death. DRAGO−/− mice are viable without macroscopic alterations. However, in p53−/− or p53+/− mice, the deletion of both DRAGO alleles statistically significantly accelerated tumor development and shortened lifespan compared with p53−/− or p53+/− mice bearing wild-type DRAGO alleles (p53−/−, DRAGO−/− mice: hazard ratio [HR] = 3.25, 95% confidence interval [CI] = 1.7 to 6.1, P < .001; p53+/−, DRAGO−/− mice: HR = 2.35, 95% CI = 1.3 to 4.0, P < .001; both groups compared with DRAGO+/+ counterparts). DRAGO mRNA levels were statistically significantly reduced in advanced-stage, compared with early-stage, ovarian tumors, but no mutations were found in several human tumors. We show that DRAGO expression is regulated both at transcriptional—through p53 (and p73) and methylation-dependent control—and post-transcriptional levels by miRNAs. Conclusions : DRAGO represents a new p53-dependent gene highly regulated in human cells and whose expression cooperates with p53 in tumor suppressor functions.