FIGURE 2.

ID1 expression is down-regulated by DEC1. A, DEC1 is induced by DNA damage in a p53-dependent manner. Western blots were prepared with extracts from MCF7 and MCF7-p53KD cells that were untreated (–) or treated (+) with 0.35 μg/ml doxorubicin (Dox) for 24 h. B, ID1 is inhibited by DEC1. Northern blots were prepared with RNAs purified from MCF7 cells that were uninduced (–) or induced (+) to express DEC1. The blots were probed with cDNAs derived from the ID1 and GAPDH genes, respectively. C and D, ID1 expression is down-regulated by DEC1. Western blots were prepared with extracts from MCF7 cells that were uninduced (–) or induced (+) to express DEC1 or mutant DEC1-R58P and from U2OS cells that were uninduced (–) or induced (+) to express DEC1. DEC1, ID1, and actin were detected by their respective antibodies.