Contents - College of Medical and Dental Sciences - University of ...
Contents - College of Medical and Dental Sciences - University of ...
Contents - College of Medical and Dental Sciences - University of ...
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The 11 th International Workshop on KSHV & Related Agents, Birmingham, UK<br />
Latency Abstract 4<br />
ROLE OF BET PROTEINS IN THE FUNCTION OF KSHV AND MHV68 LANA<br />
Magdalena Weidner-Glunde, Matthias Ottinger, Daniel Pliquet, Ronald Frank* <strong>and</strong><br />
Thomas F. Schulz<br />
Institute <strong>of</strong> Virology, Hannover <strong>Medical</strong> School, Germany<br />
*HZI Braunschweig, Germany<br />
Abstract<br />
KSHV LANA-1 is a multifunctional protein known to be involved in KSHV genome<br />
maintenance, replication <strong>and</strong> transcriptional regulation. Its homologue in murine<br />
herpesvirus 68 has been shown to contribute to establishing latency. Two members <strong>of</strong><br />
the BET protein family, Brd2/RING3 <strong>and</strong> BRD4/HUNK, which bind to chromatin via<br />
acetylated histones, were found to interact with KSHV LANA-1<strong>and</strong> MHV68 orf73 protein.<br />
In view <strong>of</strong> the participation <strong>of</strong> Brd4 in the Mediator transcriptional co-activator complex<br />
<strong>and</strong> its implication in HPV-E2-mediated transcriptional regulation, we tested whether<br />
these two proteins are involved in LANA-1 dependent transcriptional activation <strong>and</strong> KSHV<br />
episome replication.<br />
Using a peptide array covering the MHV68 orf73 we identified aa226-231 as residues<br />
interacting with recombinant Brd2/RING3. MHV68 orf73 mutants with alanine<br />
substitutions in this region failed to activate a range <strong>of</strong> cellular promoters (cyclin E, D1,<br />
D2). They also showed an altered interaction with cellular chromatin.<br />
For KSHV LANA-1 we found that siRNAs specific for Brd2 or Brd4 reduced the KSHV<br />
LANA-1 dependent replication <strong>of</strong> a plasmid containing the latent origin. In addition, a<br />
Brd2 fragment comprising the ET domain inhibited episomal replication when<br />
overexpressed transiently.<br />
Our data suggest that (I) members <strong>of</strong> the BRD/BET protein family are involved in<br />
transcriptional regulation mediated by KSHV LANA-1 <strong>and</strong> its MHV68 homologue <strong>and</strong> that<br />
(II) Brd2/RING3 plays a role in LANA-1-mediated episomal replication. These<br />
observations could serve as a basis for the development <strong>of</strong> a peptide inhibitor <strong>of</strong> the<br />
interaction between LANA-1 <strong>and</strong> Brd2 <strong>and</strong> possibly also <strong>of</strong> the KSHV latent replication.<br />
Presenting author Email: weidnerg@allmail.mh-hannover.de<br />
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