TY - JOUR
T1 - DNA Ligase IV regulates XRCC4 nuclear localization
AU - Francis, Dailia B.
AU - Kozlov, Mikhail
AU - Chavez, Jose
AU - Chu, Jennifer
AU - Malu, Shruti
AU - Hanna, Mary
AU - Cortes, Patricia
N1 - Funding Information:
We thank members of the Cortes laboratory for helpful discussions and reagents and Dr. Juan Carcamo for constructive suggestions and critical reading of the manuscript. We thank Dr. Michael R. Lieber for providing the Nalm 6 and N114P2 cells, Dr. Anna Villa for the control fibroblast NM-1. Dr. Tomas Lindahl and Dr. Michael Lieber provided the cDNA for human Ligase IV. The advice and equipment provided by the Mount Sinai Microscopy Shared Resource Facility were instrumental to perform the described studies. Work in the P.C. laboratory is supported by the National Institutes of Health ( R01 AI080755 and R01 AI070880 from NIH). D.B.F. was supported by pre-doctoral training grants given to the Immunology Institute by the National Institute of Health ( T32-A1007605-09 and 5T32A1007605-10 ).
PY - 2014/9
Y1 - 2014/9
N2 - DNA Ligase IV, along with its interacting partner XRCC4, are essential for repairing DNA double strand breaks by non-homologous end joining (NHEJ). Together, they complete the final ligation step resolving the DNA break. Ligase IV is regulated by XRCC4 and XLF. However, the mechanism(s) by which Ligase IV control the NHEJ reaction and other NHEJ factor(s) remains poorly characterized. Here, we show that a C-terminal region of Ligase IV (aa 620-800), which encompasses a NLS, the BRCT I, and the XRCC4 interacting region (XIR), is essential for nuclear localization of its co-factor XRCC4. In Ligase IV deficient cells, XRCC4 showed deregulated localization remaining in the cytosol even after induction of DNA double strand breaks. DNA Ligase IV was also required for efficient localization of XLF into the nucleus. Additionally, human fibroblasts that harbor hypomorphic mutations within the Ligase IV gene displayed decreased levels of XRCC4 protein, implicating that DNA Ligase IV is also regulating XRCC4 stability. Our results provide evidence for a role of DNA Ligase IV in controlling the cellular localization and protein levels of XRCC4.
AB - DNA Ligase IV, along with its interacting partner XRCC4, are essential for repairing DNA double strand breaks by non-homologous end joining (NHEJ). Together, they complete the final ligation step resolving the DNA break. Ligase IV is regulated by XRCC4 and XLF. However, the mechanism(s) by which Ligase IV control the NHEJ reaction and other NHEJ factor(s) remains poorly characterized. Here, we show that a C-terminal region of Ligase IV (aa 620-800), which encompasses a NLS, the BRCT I, and the XRCC4 interacting region (XIR), is essential for nuclear localization of its co-factor XRCC4. In Ligase IV deficient cells, XRCC4 showed deregulated localization remaining in the cytosol even after induction of DNA double strand breaks. DNA Ligase IV was also required for efficient localization of XLF into the nucleus. Additionally, human fibroblasts that harbor hypomorphic mutations within the Ligase IV gene displayed decreased levels of XRCC4 protein, implicating that DNA Ligase IV is also regulating XRCC4 stability. Our results provide evidence for a role of DNA Ligase IV in controlling the cellular localization and protein levels of XRCC4.
KW - DNA Ligase IV
KW - DNA repair
KW - NHEJ
KW - V(D)J recombination
KW - XRCC4
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U2 - 10.1016/j.dnarep.2014.05.010
DO - 10.1016/j.dnarep.2014.05.010
M3 - Article
C2 - 24984242
AN - SCOPUS:84903528786
SN - 1568-7864
VL - 21
SP - 36
EP - 42
JO - DNA Repair
JF - DNA Repair
ER -