Journal of General Virology

Topors, a p53 and topoisomerase I binding protein, interacts with the adeno-associated virus (AAV-2) Rep78/68 proteins and enhances AAV-2 gene expression

Stefan Weger, Eva Hammer and Regine Heilbronn

Institut für Infektionsmedizin, Abteilung Virologie, Freie Universität Berlin, Hindenburgdamm 27, D-12203 Berlin, Germany

The adeno-associated virus type 2 (AAV-2) Rep proteins are essential for AAV DNA replication and regulation of AAV gene expression. We have identified a cellular protein interacting with Rep78 and Rep68 in yeast two-hybrid analysis and in GST pull-down assays. This protein has recently been described as both a p53 (p53BP3) and a topoisomerase I interacting protein (Topors). It contains an arginine/serine-rich domain, a RING finger domain and five PEST sequences. A minimal sequence sufficient for interaction with Rep was mapped to Topors amino acids 871 to 917. We show that the same region is also involved in the interaction with p53. Rep sequences involved in interaction with Topors were mapped to Rep amino acids 172 to 481. Overexpression of Topors stimulated AAV gene expression in the absence of helper virus, suggesting a function of Topors as a transcriptional regulator.

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© 2002 SGM

This article is now available in the March 2002 print issue of JGV (vol. 83, 511–516). The complete issue of the journal may be seen in electronic form on JGV Online.