Abstract
DNA ligase IV is one of the key proteins that are associated with DNA double strand break (DNA DSB) repair through the non-homologous end joining (NHEJ) pathway. We designed 21 bp small double stranded RNA (siRNA) on the basis of its specific DNA sequence, and transfected HFLIII, normal human primary fibroblasts, with the DNA ligase IV siRNA. The RNA and protein expression levels of DNA ligase IV and several key radiological characteristics were investigated in the siRNA-transfected and control cells. Compared to the cells with mock-transfection, the RNA and protein expressions were reduced in the siRNA-transfected cells. An increase in chromosomal fragmentation and a decrease in cell survival were observed in X-irradiated cells transfected with the siRNA. The transfection with the DNA ligase IV siRNA did not make a significant effect on cell growth and the XRCC4 protein expression. These results indicate that human cells could be radiosensitized by reducing the expression of DNA ligase IV using RNA interference technology.
