Search

The contribution of adenovirus early genes, other than that of the well‐documented EIa immediate early gene, to the transcriptional regulation of the viral EIIa early transcription unit was examined. HeLa cells were transfected with EIIa‐containing plasmids and co‐transfected with distinct plasmids bearing one of the viral regions EIa, EIII or EIV. Co‐transfection with the EIV‐recombinants, but not the EIII constructs, stimulated specific transcription from the major EIIaE start site (EIIaE1) by 5‐ to 15‐fold, as concluded from quantitative S1 nuclease analysis of cytoplasmic RNA and in vitro nuclear ‘run‐on’ transcription assays. The extent of the EIV‐induced stimulation was similar to that achieved by EIa under identical conditions. However, in contrast to our observations for EIa‐mediated stimulation, where no unique EIIaE1 promoter elements were implicated, maximal induction by EIV requires sequences between positions ‐48 and ‐19 (with respect to the EIIaE1 start site).