Figure 1.

Time-dependent effect of EGF on the interaction between Sp1 and c-Jun in vivo. Confluent cells were starved for 24 h in serum-free culture medium before EGF treatment and then treated with EGF in culture medium without serum for a different time period, as indicated. Nuclear extracts were prepared and subjected to Western blotting by using antibodies specific for Sp1 and c-Jun (A and B). Nuclear extracts from EGF-treated cells were immunoprecipitated (IP) with antibodies (Ab) against Sp1 or c-Jun bound to protein A-agarose. Immunoprecipitates were subjected to 10% SDS/PAGE followed by Western blotting with antibodies against Sp1 (C and F) and c-Jun (D and E), respectively.