EBV Conference 2008 Guangzhou - Baylor College of Medicine

64 (RegID: 1259)
Daniel Portal
Institution: Brigham and Women's Hospital, Harvard University
e-mail: dportal@rics.bwh.harvard.edu
EBNA-LP RELOCALIZES SMRT/NCOR AND HDAC5 FROM MAD BODIES TO THE
NUCLEOPLASM
DANIEL PORTAL AND ELLIOTT KIEFF
Posterabstract:
Epstein-Barr nuclear antigen (EBNA) leader protein (EBNA-LP) coactivates promoters with EBNA2 and
is important for Epstein-Barr virus immortalization of B cells. EBNA2 activates transcription by
associating with RBP/CSL and displacing SMRT/NCoR-HDAC5 corepressor complex. We investigated
EBNA-LP’s role in coactivation with EBNA2 by affecting SMRT/NCoR-HDAC5 from their subnuclear
localization. At steady state, SMRT/NCoR-HDAC5 localize to Matrix-Associated Deacetylase (MAD)
Bodies as well as diffusely in the nucleus and cytoplasm. EBNA-LP’s presence completely relocalizes
SMRT/NCoR and HDAC5 from MAD bodies to a diffuse nuclear distribution. Moreover, SMRT/NCoR
and HDAC5’s diffuse distribution completely colocalizes with EBNA-LP’s distribution, but not with
active transcription as determined by H3K4 co-immunostaining, suggesting that EBNA-LP is not present
at sites of active transcription. MAD bodies’ disruption appears to be dependent on EBNA-LP’s ability to
interact with HA95, a nuclear matrix protein, since an EBNA-LP protein unable to associate with HA95 is
10 fold less efficient at relocating SMRT/NCoR and HDAC5.These data further strengthen EBNA-LP’s
role in coactivation of transcription by relocating repressors from their steady state subcellular
localization.
EBV Conference 2008 Guangzhou
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