MVM DNA replication and NS1 protein production in A9 cells and transfectants overexpressing mutant forms of PKCη. A9 cells, or derivatives stably transfected with indicated P38-driven PKCη mutant clones, were infected or not with MVMp (10 PFU/cell) and harvested at various time points (hours p.i.). Viral DNA and NS1 proteins were quantitated by Southern (upper panel) and Western blotting (lower panel), respectively. mRF, monomeric replicative intermediate form; dRF, dimeric replicative intermediate form; ss, single-stranded DNA.