Promyelocytic Leukemia Protein Interacts with Werner Syndrome Helicase and Regulates Double-Strand Break Repair in γ-Irradiation-Induced DNA Damage Responses

---

Jilai Liu^#, Yi Song^#*, Junjie Qian, Bin Liu, Yan Dong, Baolei Tian, and Zhixian Sun^*

Department of Biochemistry and Molecular Biology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, P. R. China; fax: 86-10-6817-7417; E-mail: songyibj@sina.com.cn; sunzx@nic.bmi.ac.cn

^# These authors contributed equally to this work.

^* To whom correspondence should be addressed.

Received October 18, 2010; Revision received December 30, 2010

---

We show here that γ-irradiation leads to the translocation of endogenous Werner syndrome helicase (WRN) from nucleoli to nucleoplasmic DNA double strand breaks (DSBs), and WRN plays a role in damage repair. The relocation of WRN after irradiation was perturbed by promyelocytic leukemia protein (PML) knockdown and enhanced by PML IV overexpression. PML IV physically interacted with WRN after irradiation. Amino acids (a.a.) 394 to 433 of PML were necessary for this interaction and the nucleoplasmic translocation of WRN and were involved in DSB repair and cellular sensitivity to γ-irradiation. Taken together, our results provide molecular support for a model in which PML IV physically interacts with and regulates the translocation of WRN for DNA damage repair through its 394-433 a.a. domain.

---

KEY WORDS: PML, WRN, γ-irradiation, DNA damage, DNA repair

DOI: 10.1134/S000629791105004X

---