Rad51 Targeted Adenoviral Vector Figure 3. Further truncations of the Rad51 core promoter lead to progressive loss of transcriptional activity, while the reported p53 binding site is not required for tumor selectivity of the Rad51 core promoter. Truncations of the Rad51core promoter were created to determine if all parts were necessary (see Fig. 1C) and modifications to the Rad51core promoter were constructed to evaluate the contribution of putative p53 binding sites to promoter activity (see Fig. 1E). The p53 binding sites were either mutated at conserved sites (Rad51mp53) or deleted (Rad51dp53) (as shown in Fig. 1E). (A) Luciferase assays measuring Rad51 promoter activity in 8 different cancer and non-cancer cell lines. Cells were transduced with their respective vectors at a MOI of 100. 24 hours post-infection, cells were lysed and luciferase activity of the cell lysates measured. Data are presented as mean values of independent experimental triplicates; error bars represent the standard deviation of the data values. (B) As a measure of tumor specificity, luciferase activity for each construct in each cell type was calculated as a ratio relative to its activity in normal lung fibroblasts (Wi-38). doi:10.1371/journal.pone.0028714.g003 PLoS ONE | www.plosone.org 5 December 2011 | Volume 6 | Issue 12 | e28714