Q. Zhang et al., Identification of transactivator and nuclear localization domains in the Epstein-Barr virus DNA polymerase accessory protein, BMRF1, J GEN VIROL, 80, 1999, pp. 69-74
The Epstein-Barr virus (EBV) BMRF1 gene product is an essential component o
f the viral DNA polymerase and is absolutely required for lytic virus repli
cation. In addition to its polymerase accessory protein function, we recent
ly demonstrated that BMRF1 is a transactivator, inducing expression of the
essential oriLyt promoter, BHLF1. However, the regions of BMRF1 required fo
r transactivation of BHLF1 are unknown. Here we demonstrate that the carbox
y-terminal portion of the BMRF1 protein (amino acids 378-404), although not
required for DNA binding or polymerase processivity function, is required
for transactivator function as well as nuclear localization. Site-directed
mutagenesis of this region allowed us to separate the transactivator and nu
clear localization motifs of BMRF1. The two DNA-binding domains of BMRF1 ar
e also required for efficient transactivation of the BHLF1 promoter.