A potential NES of the Epstein-Barr virus nuclear antigen 1 (EBNA1) does not confer shuttling

The Epstein-Barr virus nuclear antigen 1 (EBNA1) is a multifunctional protein involved in the replication and maintenance of the viral episome. We identified a potential Rev-like nuclear export signal (NES) which, however, does not confer the export of EBNA1, In the yeast two-hybrid system EBNA1 does not bind to the nuclear exporter Crm1p, In spite of the RNA-binding ability of EBNA1 and its structural homologies to RNA binding proteins like hnRNP U and/or Al, EBNA1 does not shuttle to the cytoplasm in heterokaryon analysis. We propose the function of the RNA binding of EBNA1 in retaining RNAs to the nucleus. (C) 1999 Federation of European Biochemical Societies.