THE EQUINE HERPESVIRUS-1 GENE-63 RING FINGER PROTEIN PARTIALLY COMPLEMENTS VMW110, ITS HERPES-SIMPLEX VIRUS TYPE-1 COUNTERPART

All alpha herpesviruses of known DNA sequence have been found to encod e a protein with similarities to immediate early protein Vmw110 (ICP0) of herpes simplex virus type 1 (HSV-1). The conserved portion of this family of proteins is a characteristic zinc binding module, known as a RING finger or C3HC4 domain. Examples of RING finger domains occur i n many other proteins of diverse evolutionary origin and function. Rec ently, the solution structure of the equine herpesvirus 1 (EHV-1) RING finger protein, encoded by gene 63, has been solved. To investigate w hether this structure could be considered to be a paradigm of herpesvi rus RING domains, we have constructed a recombinant HSV-1 which expres ses the EHV-1 gene 63 protein (EHVg63) in place of Vmw110. Comparison of the growth properties of the recombinant with those of wildtype and Vmw110-defective viruses indicates that EHVg63 is able to fulfil part ially, but not completely, the roles of Vmw110 during virus growth in tissue culture.