PARP-1 Interaction with VP1 Capsid Protein Regulates Polyomavirus Early Gene Expression super( approximately equal to )

• Published in: Journal of molecular biology Vol. 363; no. 4; pp. 773 - 785
• Main Authors: Carbone, M, Reale, A, Di Sauro, A, Sthandier, O, Garcia, MI, Maione, R, Caiafa, P, Amati, P
• Format: Journal Article
• Language: English
• Published: 03-11-2006
• Subjects: Polyomavirus
• ISSN: 0022-2836
• DOI: 10.1016/j.jmb.2006.05.077

Poly(ADP-ribose)polymerases are involved in fundamental cellular events as well as they seem to be associated to some viral infection process. In this work, the poly(ADP-ribose)polymerase-1 (PARP-1) role in the polyomavirus life cycle has been investigated. Early viral transcription was reduced by competitive inhibitors of PARPs in Swiss 3T3 cells and almost abolished in PARP-1 knockout fibroblasts and in wild-type fibroblasts when PARP-1 was silenced by RNA interference. In vivo chromatin immunoprecipitation assays showed that poly(ADP-ribosyl)ation (poly(ADP-ribose)) facilitates the release of the capsid protein viral protein 1 (VP1) from the chromatin of infecting virions. In vitro experiments demonstrated that VP1 stimulates the enzymatic activity of PARP-1 and binds non-covalently both protein-free and PARP-1-bound poly(ADP-ribose). Our studies suggest that PARP-1 promotes the complete VP1 displacement from viral DNA favouring the viral early transcription.