SHOPE FIBROMA VIRUS RING FINGER PROTEIN N1R BINDS DNA AND INHIBITS APOPTOSIS

Shope fibroma virus (SFV) N1R gene encodes a RING finger protein that localizes to virus factories within the cytoplasm of infected cells. A ltered proteins, with deletions and site-specific mutations, were tran siently expressed in vaccinia virus-infected cells to discern regions of the protein that are required for localization. We have determined that at least part of the RING finger region is necessary for localiza tion but that the RING motif alone is not sufficient. A chimeric prote in, however, in which the RING finger region of the herpes simplex vir us-1 ICP0 protein replaces the SFV N1R RING motif does localize to vir us factories, A region of five highly conserved amino acids at the ami no terminus of SFV N1R is also critical for localization. We report th at the SFV N1R protein binds double- and single-stranded DNA, suggesti ng a mechanism for localization, and that overexpression of this prote in in vaccinia virus-infected cells reduces apoptosis-associated fragm entation of nuclear DNA. (C) 1998 Academic Press.