Reversal of p300 depletion-dependent premature S phase induction.
(A) Inhibition of premature S phase induction in
p300-depleted MCF10A cells by overexpression of MAD.
Serum-starved MCF10A cells were coinfected with AS Ad vectors at 200
pfu/cell with or without Ad-MAD (100 pfu/cell), which expresses MAD
protein. Ad-β-gal was always used to maintain the multiplicity of
infection uniform in all experiments. (B) Reversal of
early S phase entry in p300-depleted cells. Serum-starved MCF10A cells
were coinfected with either AS p300 sequences and AS-c-Myc or AS-c-Jun.
Ad-β-gal was used to maintain the multiplicity of infection.
(C) Inhibition of c-MYC protein synthesis in p300
depleted cells. Serum-starved MCF10A cells were coinfected with
different adenoviral vectors in combinations as indicated below. In
lanes 1, 5, 9, and 13 Ad-β-gal was mixed with AS-c-Myc; in lanes 2,
6, 10, and 14 AS-1 was mixed with AS-c-Myc; in lanes 3, 7, 11, and 15
Ad-β-gal was mixed with Ad -β-gal and in lanes 4, 8, 12, and 16,
Ad-β-gal was mixed with AS-1. Protein lysates obtained from these
cells at different periods of infection were assayed for c-MYC protein
levels by Western blot analysis. Western blot membrane shown
(Upper) was reprobed with α-actin antibody.