Regulation of homologous recombinational repair by lamin B1 in radiation-induced DNA damage.
DNA double-strand breaks (DSBs) are the major lethal lesion induced by ionizing radiation (IR). RAD51-dependent homologous recombination (HR) is one of the most important pathways in DSB repair and genome integrity maintenance. However, the mechanism of HR regulation by RAD51 remains unclear. To understand the mechanism of RAD51-dependent HR, we searched for interacting partners of RAD51 by a proteomics analysis and identified lamin B1 in human cells. Lamins are nuclear lamina proteins that play important roles in the structural organization of the nucleus and the regulation of chromosome functions. Immunoblotting analyses revealed that siRNA-mediated lamin B1 depletion repressed the DNA damage-dependent increase of RAD51 after IR. The repression was abolished by the proteasome inhibitor MG132, suggesting that lamin B1 stabilizes RAD51 by preventing proteasome-mediated degradation in cells with IR-induced DNA damage. We also showed that lamin B1 depletion repressed RAD51 focus formation and decreased the survival rates after IR. On the basis of these results, we propose that lamin B1 promotes DSB repair and cell survival by maintaining the RAD51 protein levels for HR upon DSB induction after IR.
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Ning-Ang
NA
Liu
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Jiying
J
Sun
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Kazuteru
K
Kono
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Yasunori
Y
Horikoshi
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Tsuyoshi
T
Ikura
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Xing
X
Tong
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.
Tokuko
T
Haraguchi
*Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, and Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Hiroshima, Japan; Department of Mutagenesis, Laboratory of Chromatin Dynamics, Radiation Biology Center, Kyoto University, Kyoto, Japan; Laboratory Center, Medical College of Soochow University, Suzhou, China; and Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan ktashiro@hiroshima-u.ac.jp.
Satoshi
S
Tashiro
D002453:Cell Cycle / Q000235:genetics / Q000528:radiation effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage; D057809:HEK293 Cells; D006367:HeLa Cells; D059765:Homologous Recombination; D006801:Humans; D015151:Immunoblotting; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D018613:Microscopy, Confocal; D011485:Protein Binding; D055550:Protein Stability; D034622:RNA Interference; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D059767:Recombinational DNA Repair; D014965:X-Rays
D034921:Lamin Type B; D051135:Rad51 Recombinase
B-type lamins; RAD51; nuclear envelope; progeria syndrome; recombinational DNA repair