Rafael J. Yáñez-Muñoz, Modesto Redrejo-Rodríguez, Ramón García-Escudero, María L. Salas and José Salas (2006) African Swine Fever Virus Protein pE296R Is a DNA Repair Apurinic/Apyrimidinic Endonuclease Required for Virus Growth in Swine Macrophages . Journal of Virology, 80 (10). pp. 4847–4857. ISSN 0022-538X
Full text access: Open
We show here that the African swine fever virus (ASFV) protein pE296R, predicted to be a class II apurinic/apyrimidinic (AP) endonuclease, possesses endonucleolytic activity specific for AP sites. Biochemical characterization of the purified recombinant enzyme indicated that the Km and catalytic efficiency values for the endonucleolytic reaction are in the range of those reported for Escherichia coli endonuclease IV (endo IV) and human Ape1. In addition to endonuclease activity, the ASFV enzyme has a proofreading 3′→5′ exonuclease activity that is considerably more efficient in the elimination of a mismatch than in that of a correctly paired base. The three-dimensional structure predicted for the pE296R protein underscores the structural similarities between endo IV and the viral protein, supporting a common mechanism for the cleavage reaction. During infection, the protein is expressed at early times and accumulates at later times. The early enzyme is localized in the nucleus and the cytoplasm, while the late protein is found only in the cytoplasm. ASFV carries two other proteins, DNA polymerase X and ligase, that, together with the viral AP endonuclease, could act as a viral base excision repair system to protect the virus genome in the highly oxidative environment of the swine macrophage, the virus host cell. Using an ASFV deletion mutant lacking the E296R gene, we have determined that the viral endonuclease is required for virus growth in macrophages but not in Vero cells. This finding supports the existence of a viral reparative system to maintain virus viability in the infected macrophage.
This is a Published version This version's date is: 01/05/2006 This item is peer reviewed
https://repository.royalholloway.ac.uk/items/a081ff5e-dd63-7b2d-0f28-5ae8d4405ffc/1/
Deposited by () on 25-Jan-2011 in Royal Holloway Research Online.Last modified on 25-Jan-2011
© 2006, American Society for Microbiology whose permission to mount this version for private study and research is acknowledged.