Screening of new target genes specifically activated by deregulated E2F

To identify genes specifically activated by deregulated E2F, we examined gene expression profiles using human normal fibroblasts (HFFs), which were starved of serum and re-stimulated with serum, over-expressed with E2F1 or expressed with adenovirus E1a to forcedly inactivate RB. To identify genes activated by growth stimulation, human normal fibroblasts (HFFs) were starved of serum for 48 hr, infected with control virus, restimulated with serum or left serum-starved for 18 hr and harvested. To identify genes actived by deregulated E2F, HFFs were starved of serum for 48 hr, infected with control virus, adenovirus expressing E2F1 or adenovirus E1a, further cultured in the absence of serum for 18 hr and harvested. Gene expression profiles of ecach sample were examined by DNA microarray.