Figure 1.

53BP1 interacts with BLM and RAD51 during replication stress. (A) Levels of 53BP1, BLM, and RAD51 in nuclear extracts from NHFs. Nuclear extracts were prepared from NHFs grown in the absence or presence of HU and after postwash (PW). Western blots were performed with anti-53BP1, anti-BLM, anti-RAD51, and anti-TBP antibodies. (B–D) BLM, RAD51, and 53BP1 are present in the same complex during replication stress. Reciprocal IPs with nuclear extracts were performed with anti-BLM (B), anti-53BP1 (C), and anti-RAD51 (D) antibodies and the corresponding IgGs. The IPs were probed with self-antibody or with antibodies against BLM, 53BP1, and RAD51 to check for interactions.