Fachbereich Veterinärmedizin



    Characterization of human herpesvirus 6A/B U94 as ATPase, helicase, exonuclease and DNA-binding proteins (2015)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Trempe, Frédéric
    Gravel, Annie
    Dubuc, Isabelle
    Wallaschek, Nina (WE 5)
    Collin, Vanessa
    Gilbert-Girard, Shella
    Morissette, Guillaume
    Kaufer, Benedikt B (WE 5)
    Flamand, Louis
    Nucleic acids research; 43(12) — S. 6084–6098
    ISSN: 1362-4962
    URL (Volltext): http://edocs.fu-berlin.de/docs/receive/FUDOCS_document_000000023066
    DOI: 10.1093/nar/gkv503
    Pubmed: 25999342
    Institut für Virologie

    Robert-von-Ostertag-Str. 7-13
    Gebäude 35
    14163 Berlin
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    Abstract / Zusammenfassung

    Human herpesvirus-6A (HHV-6A) and HHV-6B integrate their genomes into the telomeres of human chromosomes, however, the mechanisms leading to integration remain unknown. HHV-6A/B encode a protein that has been proposed to be involved in integration termed U94, an ortholog of adeno-associated virus type 2 (AAV-2) Rep68 integrase. In this report, we addressed whether purified recombinant maltose-binding protein (MBP)-U94 fusion proteins of HHV-6A/B possess biological functions compatible with viral integration. We could demonstrate that MBP-U94 efficiently binds both dsDNA and ssDNA containing telomeric repeats using gel shift assay and surface plasmon resonance. MBP-U94 is also able to hydrolyze adenosine triphosphate (ATP) to ADP, providing the energy for further catalytic activities. In addition, U94 displays a 3' to 5' exonuclease activity on dsDNA with a preference for 3'-recessed ends. Once the DNA strand reaches 8-10 nt in length, the enzyme dissociates it from the complementary strand. Lastly, MBP-U94 compromises the integrity of a synthetic telomeric D-loop through exonuclease attack at the 3' end of the invading strand. The preferential DNA binding of MBP-U94 to telomeric sequences, its ability to hydrolyze ATP and its exonuclease/helicase activities suggest that U94 possesses all functions required for HHV-6A/B chromosomal integration.