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. Author manuscript; available in PMC: 2015 Jul 29.
Published in final edited form as: J Biol Chem. 2003 Feb 13;278(16):14013–14019. doi: 10.1074/jbc.M209702200

Fig. 4. Effects of MAPK on p300 transactivation activity.

Fig. 4

A, effect of PDx and genistein on p300 transactivation activity. HeLa cells where co-transfected with a plasmid expressing G4.p300 and with the GAL4-luciferase reporter (pFR-luc). The transfected cells were divided evenly and exposed to Me2SO (DMSO), PDx (75 μM), or genistein for 6 h in normoxia or hypoxia immediately before the luciferase assays. B, dose-dependent effect of PDx on p300 activity. HeLa cells were transfected as in B, and increasing amounts of PDx were used, as indicated (in μM). C, dose-dependent effects of PDx on the transactivation domains of p300TD. HeLa cells were transfected with plasmid G4.p300TD, expressing the transactivation domain of p300 (aa 1751–2414), and the cells were exposed to increasing concentrations of PDx. D, effects of overexpression of MEK1 on the transactivation activity of p300TD. Plasmid expressing MEK1 (2 μg) was co-transfected with pG4.p300TD (2 μg) and the luciferase-reporter (pFR-Luc; 2 μg). Luciferase activity was expressed as -fold increase over the co-transfected vector control. E, direct phosphorylation of p300TD in vitro by MAPK. GST.p300TD was expressed in and purified from BL21 cells and used in MAPK kinase assays. RLU, relative light units.