In MCF7 cells, overexpression of SUG-1 blocks the transcription of
RARα target genes and the degradation of RARα.
A, MCF7 cells were transfected with a vector encoding SUG-1 and were
RA-treated. SRC-3 and RARα degradation as well as the efficiency of
SUG-1 overexpression were analyzed by immunoblotting. B,
overexpression of SUG-1 blocks the RA-induced expression of a DR5-tk
luciferase reporter gene. The values are the mean ± S.D. of triplicate
experiments. The efficiency of SUG-1 overexpression is shown in the right
panel. C and D, overexpression of SUG-1 reduces the RA-induced
expression of Cyp26A1, as assessed by qRT-PCR. The results are the
average of three experiments that agreed within 15%. E and
F, in MCF7 cell knockdown for SUG-1, re-expression of SUG-1 in excess
amounts blocks the degradation of RARα and the expression of a
DR5-tk-Luc reporter gene. The values are the mean ± S.D. of three
independent experiments.