HUMAN CYTOMEGALOVIRUS IE1 AND IE2 PROTEINS BLOCK APOPTOSIS

Human cytomegalovirus-infected fibroblasts are resistant to the induct ion of apoptosis by superinfection with a mutant adenovirus unable to produce the viral E1B 19-kDa protein that normally causes an E1A prote in-mediated apoptotic response. Two cytomegalovirus gene products that block apoptosis were identified. The IE1 and IE2 proteins each inhibi t the induction of apoptosis by tumor necrosis factor or or by the E1B 19-kDa-protein-deficient adenovirus but not by irradiation with UV li ght. Our results suggest a new physiological role for the IE1 and IE2 proteins in the human cytomegalovirus replication cycle.