Effect of human cytomegalovirus on replication of SV40 origin and the expression of T antigen.

Human cytomegalovirus (HCMV) induces replication of the cloned SV40 origin of DNA replication in both productive and nonproductive infections. HCMV-induced replication of the SV40 DNA origin required the presence of T antigen. Human embryonic lung (HEL) cells were found to be fully permissive for SV40 origin replication only in the presence of HCMV gene expression. In addition, expression of plasmid encoded SV40 T antigen in HEL cells was only induced in the presence of HCMV. Cotransfection of the SV40-cloned origin of replication and seven overlapping cosmids containing the entire HCMV genome is capable of stimulating replication of the SV40 origin. We conclude that induction of the SV40 origin of replication by HCMV is (i) not due to any component of the HCMV virion, (ii) has a requirement for T antigen expression, (iii) occurs in an SV40 nonproductive cell, when T antigen expression is induced by HCMV gene expression.