Mutational analysis of the J recombination signal sequence binding protein(RBP-J)/Epstein-Barr virus nuclear antigen 2 (EBNA2) and RBP-J/Notch interaction

Epstein-Barr virus nuclear antigen 2 (EBNA2) and the Notch protein both fun ction within the nucleus as transcriptional adaptor proteins. EBNA2 plays a key role during the immortalization of primary B-cells by Epstein-Barr vir us (EBV). Notch proteins are involved in lymphomagenesis as well as in mult iple cell fate decisions during tissue differentiation and development. Bot h, EBNA2 and Notch interact with the DNA binding protein RBP-J and thereby gain access to the promoter of their target genes. In order to identify reg ions within the J recombination signal sequence binding protein (RBP-J), th at are relevant for either the Notch or the EBNA2 interaction, we have perf ormed a mutational analysis of RBP-J. A library of RBP-J mutants was screen ed by a reverse two-hybrid system for alleles that fail to bind to either E BNA2 or Notch. The sequence analysis of these alleles reveals that a limite d and particularly distinct number of amino-acid positions are relevant for either interaction only. Given the important role of RBP-J in B-cell immor talization, the EBNA2/RBP-J protein-protein interaction could be a candidat e target for therapeutic intervention in EBV related diseases.