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. Author manuscript; available in PMC: 2010 Apr 30.
Published in final edited form as: J Biol Chem. 2002 Apr 15;277(25):22222–22230. doi: 10.1074/jbc.M202844200

FIG. 4. Egr-1- and PMA-induced expression of wild-type and mutant derivatives of the MAO B promoter.

FIG. 4

A, time course of Egr-1 expression during PMA treatment. Western blot was performed using 50 µg of nuclear proteins from HepG2 cells treated with 150 nm PMA for various times. B, HepG2 cells were co-transfected with 1 µg of wild-type pB −246/−66Luc MAO B promoter construct and increasing amounts of an expression vector for Egr-1 under the control of a cytomegalovirus promoter. C, 1 µg of wild-type pB −246/−66 MAO B promoter construct or different mutants of pB −246/−66Luc were transfected with 1 µg of vector (pCMV) or Egr-1 expression plasmid. D, HepG2 cells were transfected with 1 µg of wild-type pB −246/−99 construct or different mutants of pB−246/−99Luc and treated with 150 nM PMA 16 h prior to harvesting or left untreated. E, effect of coexpression of Sp1, Sp3, and Egr-1 on promoter activity was shown. Five hundred nanograms of the expression plasmids were co-transfected with 1 µg of the proximal promoter construct pB−246/−99Luc into HepG2 cells. The amount of transfected plasmids was kept constant (2 µg) using a vector construct (pCMV). The endogenous MAO B activities in HepG2 cells that were cotransfected with the pB −246/−66 MAO B promoter construct and Sp1, Sp3, or Egr-1 or various combinations as indicated are shown at the bottom by Northern blot. Data are the mean ± S.D. from three independent experiments with duplicates for each experiment.