title: p53 inhibits adeno-associated viral vector integration.
abstract: Adeno-associated viral (AAV) vectors preferentially integrate into the genome of cells that are defective in DNA repair, such as occurs with DNA-PKcs deficiency or poly(ADP-ribose) polymerase-1 down-regulation. As the tumor suppressor protein p53 regulates the transcription of many genes involved in DNA repair, we sought to determine whether functional p53 affects the efficiency of AAV integration. p53 is mutated in more than 50% of cancers, and site-specific integration of AAV into the AAVS1 site of human chromosome 19 has frequently been observed in transformed cancer cell lines, but rarely seen in primary cells or in vivo. We therefore hypothesized that p53-negative cells would be more permissive to AAV integration than p53-positive cells. The integration of a rep- and green fluorescent protein-encoding recombinant AAV vector was quantified in p53-expressing and p53-deficient HCT116 colon cancer cells. Our results show that there is a higher efficiency of AAV integration in p53-negative cells compared with p53-positive cells, indicating that p53 does indeed inhibit AAV integration. Further experiments suggest that this p53-mediated block to AAV integration is likely to be through binding of p53 to the AAV Rep protein and the consequent inhibition of Rep activity during AAV integration.
authors.affiliation: Division of Rheumatic and Autoimmune Diseases, Department of Medicine, Institute of Human Genetics, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Jeana
authors.initials: J
authors.lastname: Zacharias
authors.forename: Liudmila G
authors.initials: LG
authors.lastname: Romanova
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Menk
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Philpott
mesh_terms: D000229:Dependovirus / Q000235:genetics / Q000502:physiology*; D005822:Genetic Vectors; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D016662:Virus Integration
chemical_list: D016159:Tumor Suppressor Protein p53