(A) Schematic representation of the Rad51 promoter linked to a luciferase reporter gene. MCF-7 cells were transfected with the Rad51-Luc or the control pGL3-luc reporter together with an expression vector encoding cyclin D1. The data are shown as mean ±SEM for N>5 separate transfections. P<0.01 (B) The Rad51-luc reporter gene was transfected into MCF-7 cells and treated with E2 and a series of kinase inhibitors: PI3K inhibitor (100 nM LY294002), HDAC inhibitor (100 nM Trichostatin A (TSA)), JNK inhibitor (5 μM SP600125), ATM inhibitor (10 μM KU55933), ATM/ATR inhibitor (5 mM Caffeine), DNA-PK inhibitor (10 μM NU7026), casein kinase-2 (CK2) inhibitor (100 μM TBB), or vehicle (DMSO) control. (D) ATM is a co-activator of E2-stimulated induction of the Rad51 promoter in MCF-7 cells. MCF-7 cells were transfected with the Rad51-luc or the control pGL3-luc reporter together with the expression vector encoding ATM, ATR, or vector control pCDNA3 and treated with 10 nM E2 or vehicle ethanol control. Data are mean ±SEM for 3 separate transfections.