Utilization of microRNAs with decreased expression levels in response to X-ray irradiation for fine-tuning radiation-controlled gene regulation.

We previously developed a promoter that was responsive to radiation by randomly combining cis-elements of transcription factors that are activated in response to radiation in prostate cancer cells. The promoter enhanced the expression of the luciferase gene linked downstream by more than 10-fold 12 h after X-ray irradiation at 10 Gy. However, without radiation, it still significantly drove its expression.