title: Real-time evaluation of p53 oscillatory behavior in vivo using bioluminescent imaging.
abstract: p53 is a key mediator of cellular response to stress, and, although its function has been carefully evaluated in vitro, noninvasive evaluation of the transcriptional activity of p53 in live animals has not been reported. To this end, we developed a transgenic mouse model wherein the firefly luciferase gene expression was dependent on the p53-responsive P2 promoter from the murine double minute 2 (MDM2) gene. Bioluminescence activity following ionizing radiation was shown to be dose, time, and p53 dependent. In addition, expression of both p53 and its activated form as well as the expression of p53 target genes (MDM2 and p21) correlated with bioluminescence activity. Temporal evaluation of p53 activity following ionizing radiation showed a distinct oscillatory pattern, which confirmed the oscillations observed previously in cultured cells. In addition, the kinetics of oscillations were altered by pretreatment with radiation-modifying agents. These results show the use of this mouse model in enhancing our understanding of the transcriptional role of p53 in vivo.
authors.affiliation: Department of Radiation Oncology, University of Michigan Medical Center, 1331 East Ann Street, Ann Arbor, MI 48109, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hamstra
authors.forename: Mahaveer S
authors.initials: MS
authors.lastname: Bhojani
authors.forename: Laura B
authors.initials: LB
authors.lastname: Griffin
authors.forename: Bharathi
authors.initials: B
authors.lastname: Laxman
authors.forename: Brian D
authors.initials: BD
authors.lastname: Ross
authors.forename: Alnawaz
authors.initials: A
authors.lastname: Rehemtulla
mesh_terms: D000818:Animals; D001683:Biological Clocks; D004249:DNA Damage; D005246:Feedback; D016158:Genes, p53; D049409:Luciferases, Firefly / Q000235:genetics; D008163:Luminescent Measurements / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation
chemical_list: D016159:Tumor Suppressor Protein p53; D049409:Luciferases, Firefly; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2