Figure 5.

 ATF-2 and p300 cooperate to transactivate the c-jun promoter in F9 cells. F9 cells that had been stably transfected with 5 μg of −730/+874 c-Jun CAT (wild type; lanes 1–17,25–30,33,34) and 5 μg of −730/+874 c-Jun CAT–m182/175 (mDRE; lanes 18–24,31,32) were cotransfected with 4 μg of pCMV–ATF-1 (lanes 6–9), pCMV–ATF-2 (lanes 10–13), pCMV–ATF-2 Δ(amino acids 112–350) (lanes 25–27) or pCMV–ATF-3 (lanes 14–17) in the presence of the pACT–p300 expression plasmid (lanes 6–17,21–27) or pACT–p300 Δ(amino acids 963–1571) (lanes 28–30), or pCMV-E1A (lanes 32,34) plus 2 μg of pRSVLacZ (lanes 1–34), as indicated. The cells were incubated for 72 hr and CAT assays were performed with extracts in which the amount of protein had been normalized by the activity of β-galactosidase. In some cases, F9 cells were incubated with 3 × 10⁻⁷ m RA (lanes 31,33). The percent conversion of CAT to its acetylated form is indicated. (Lane 1) Wild type only; (lanes 2–4,18–20) 4 μg of pCMV–ATF-1, pCMV–ATF-2, or pCMV–ATF-3; (lane 5) 4 μg of pACT–p300; (lanes 6–9,10–13,14–17,25–30) 1.0, 4.0, and 8.0 μg of pCMV–ATF-1, pCMV–ATF-2, pCMV–ATF-2 Δ(amino acids 112–350) or pCMV–ATF-3 plasmid, respectively, in the presence of 4 μg of pACT–p300 (lanes 6–17,25–27) or of pACT–p300 Δ(amino acids 965–1571) (lanes 28–30), respectively.