EBV Conference 2008 Guangzhou - Baylor College of Medicine

14 (RegID: 1153; 1154)
Friedrich Grasser
Institution:Universitätsklinikum des Saarlandes
e-mail:graesser@uks.eu
METHYLATION GENERATES FUNCTIONALLY DIFFERENT SUBSPECIES OF THE
EPSTEIN-BARR VIRUS NUCLEAR ANTIGEN 2
Henrik Gross, Alfredo Mamiani, Stephanie Barth, Christine Hennard, Ursula-Zimber-Strobl, Elisabeth
Kremmer, and Friedrich A. Grasser
Oralabstract:
The Epstein-Barr virus-encoded nuclear antigen 2 (EBNA2) is essential for the transformation of
B-lymphocytes by EBV. The symmetrically dimethylated Arginine (sDMA) residues within its
Arginine-Glycine (RG) repeat confer binding to the survival of motor neurons protein (SMN). With newly
developed methylation-specific monoclonal antibodies, we now show that the RG repeat also contains
non-methylated (NMA) as well as asymmetrically dimethylated Arginines (aDMA). Non-methylated
EBNA2 sediments in a low molecular weight fraction, while the majority of aDMA- and sDMA-modified
EBNA2 migrates to high-molecular mass fractions in a sucrose gradient. The methylation status of the
EBNA2-subfractions did not change upon lytic viral replication but was substantially reduced by the
methylation inhibitor AdOx. Non-methylated EBNA2 did not bind to DNA in an electrophoretic mobility
shift assay (EMSA) but could be transformed in vitro to a methylated, DNA-binding form that was
supershifted by the aDMA-specific antibody while the sDMA-specific antibody did not induce a
supershift. Our data indicate that methylation of EBNA2 generates functionally divergent subspecies and
that methylation is a prerequisite for DNA-binding by EBNA2 via association with the transcription factor
RBPJκ.
EBV Conference 2008 Guangzhou
- 52 -