Project: Research project

Project Details


The long term objective of this research is to discern the mechanism by
which Epstein-Barr virus induces proliferation and immortalization of B
cells; EBV-induced proliferation can lead to lymphomas in immunosuppressed
individuals. This information is essential to our understanding of the
pathogenesis and persistence of EBV as well as our comprehension of the
process of B cell proliferation, a highly regulated event central to immune
function. Latent infection by EBV results in expression of 6 viral nuclear
proteins (EBNAs) and 3 viral membrane proteins followed by proliferation
and immortalization of the infected B cells. We propose to identify the
functions of the latent infection proteins and the cellular pathways
through which they act. Specifically, we propose to: 1) determine a
biochemical basis of EBNA2-induced immortalization of B cells, 2) elucidate
EBNA function by characterization of associated cellular proteins and 3)
establish the biochemical effects of individual EBV latent infection
proteins in primary B cells. Our preliminary studies have indicated that
interaction of one of these nuclear proteins, EBNA2, binds to the
retinoblastoma protein, Rb, and that EBNA2 contains sequences which are
homologous to the Rb-binding domain of SV40 large T antigen. We propose to
determine whether the interaction is mediated via these sequences by using
specific peptides to inhibit the interaction and by examining the ability
of EBNA2 deletion mutants to bind Rb. The EBNA2 sequence differs in some
residues which are believed to be invariant and therefore these results
will provide information about the relative importance of these residues.
We have recently demonstrated that other cellular proteins bind to the
EBNAs; these cellular proteins are likely to include not only proteins
which have been demonstrated to associate with DNA tumor virus transforming
proteins, such as Rb, but also proteins which are involved in the exquisite
control of B cell proliferation as well as proteins involved in other
cellular processes such as transcription factors. Using EBNA fusion
proteins to screen a cDNA expression library, we propose to isolate the
cDNAs encoding cellular proteins which bind to the EBNAs. The role of
individual viral proteins will be investigated by transfection of viral
genes into primary B cells; we will examine activation markers and
radiolabelled nucleotide incorporation to determine the effects on
activation and proliferation of B cells. These studies will allow us to
define the biochemical function of the EBV latent proteins.
Effective start/end date4/1/923/31/93


  • National Cancer Institute

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