PARP1-dependent Kinetics of Recruitment of MRE11 and NBS1 Proteins to Multiple DNA Damage Sites

Endogenous PARP1 interacts with MRE11 at DSB sites. Shown is in vivo IP analysis of PARP1 (a) and MRE11 protein (b) using SK-N-SH whole cell extracts (WCE) treated or not with etoposide (50 μm, 1 h). c, wild-type MEF cells (left) or PARP1-deficient cells (right) were treated or not with 50 μm etoposide. One hour later, cells were fractionated with successive detergent extraction, and extracts were immunoblotted as indicated. d, quantification of DNA damage-induced 53BP1 foci per cell in PARP1-deficient cells transfected or not with a GFP-PARP1 vector. Error bars, S.E. WB, Western blot.