Suppression of Short Tract Gene Conversion in Episomal DNA by p53 Reduction

Abstract

The loss of the p53 tumor suppressor protein causes genomic instability. The double strand break is the most severe form of DNA damage, and homologous recombination (HR) acts as a defense against it. In this study, the effects of p53 reduction on HR were investigated, using plasmid DNA in human U2OS cells. The plasmid DNA was designed to contain two inactivated kanamycin resistance genes that reconstitute the functional gene after HR. The p53 protein was knocked-down by siRNA, and then linearized plasmid DNA was introduced into the knockdown cells. The knockdown of p53 reduced the frequency of short tract gene conversion in the plasmid. These results suggested that p53 may enhance the HR of episomal DNA in human cells.