Figure 2.

p53 and doxorubicin treatment activate promoters of miR-16-2 and miR-26a genes in luciferase assay. (a) Shown is the scheme of the promoter and its deletion mutant for the miR-26a-1 gene situated in front of the luciferase gene. U2-OS cells stably expressing scrambled shRNA (U2-OS scr) versus p53-specific shRNA (U2-OS KDp53) were treated or not treated with doxorubicin for 14 h before harvesting. Cell extracts were then prepared, normalized for transfection efficiency by measuring beta-galactosidase activity and assayed for luciferase activity. Empty luciferase vector with minimal HSP70 promoter was used as negative control. (b) Shown are three fragments of the miR-16-2 promoter, which were assayed for their ability to drive luciferase activity in response to doxorubicin. Cells were treated and assayed as described above. A fragment of the miR-16-1 promoter driving transcription of the luciferase gene that does not respond to p53 was used as a negative control