Inhibition of SV40 DNA replication by Rous sarcoma virus LTR enhancer.

Simian virus 40 (SV40) late region recombinant constructs containing the Rous sarcoma virus (RSV) src gene along with RSV enhancer stimulated expression but completely abolished SV40 DNA replication. Constructs, in which the heterologous enhancer sequences were omitted, did replicate normally in African green monkey kidney cells and, in the presence of helper virus, gave rise to infectious progeny. Inhibition of SV40 DNA replication follows a cis-acting mechanism and is most likely due to a conformational change of the SV40 chromatin structure.