Involvement of the reparative DNA polymerase pol X of african swine fever virus in the maintenance of viral genome stability in vivo

Abstract

The function of the African swine fever virus (ASFV) reparative DNA polymerase, Pol X, was investigated in the context of virus infection. PolXis a late structural protein that localizes at cytoplasmic viral factories duringDNAreplication. Using an ASFV deletionmutant lacking the PolXgene, we have shown that PolXis not required for virus growth in Vero cells or swine macrophages under one-step growth conditions. However, at a low multiplicity of infection, when multiple rounds of replication occur, the growth of the mutant virus is impaired in swine macrophages but not in Vero cells, suggesting that PolXis needed to repair the accumulatedDNA damage. The replication of the mutant virus in Vero cellspresents sensitivity to oxidative damage, and mutational analysis of viral DNAshows that deletion of PolXresults in an increase in the mutation frequency in macrophages. Therefore, our data reveal a biological role for ASFV PolXin the context of the infected cell in the preservation of viral genetic information. © 2013, American Society for Microbiology.