TY - JOUR
T1 - Structure-specific endonucleases Xpf and Mus81 play overlapping but essential roles in DNA repair by homologous recombination
AU - Kikuchi, Koji
AU - Narita, Takeo
AU - Pham, Van T.
AU - Iijima, Junko
AU - Hirota, Kouji
AU - Keka, Islam Shamima
AU - Mohiuddin,
AU - Okawa, Katsuya
AU - Hori, Tetsuya
AU - Fukagawa, Tatsuo
AU - Essers, Jeroen
AU - Kanaar, Roland
AU - Whitby, Matthew C.
AU - Sugasawa, Kaoru
AU - Taniguchi, Yoshihito
AU - Kitagawa, Katsumi
AU - Takeda, Shunichi
PY - 2013/7/15
Y1 - 2013/7/15
N2 - DNA double-strand breaks (DSB) occur frequently during replication in sister chromatids and are dramatically increased when cells are exposed to chemotherapeutic agents including camptothecin. Such DSBs are efficiently repaired specifically by homologous recombination (HR) with the intact sister chromatid. HR, therefore, plays pivotal roles in cellular proliferation and cellular tolerance to camptothecin. Mammalian cells carry several structure-specific endonucleases, such as Xpf-Ercc1 and Mus81-Eme1, in which Xpf and Mus81 are the essential subunits for enzymatic activity. Here, we show the functional overlap between Xpf and Mus81 by conditionally inactivating Xpf in the chicken DT40 cell line, which has no Mus81 ortholog. Although mammalian cells deficient in either Xpf or Mus81 are viable, Xpf inactivation in DT40 cells was lethal, resulting in a marked increase in the number of spontaneous chromosome breaks. Similarly, inactivation of both Xpf and Mus81 in human HeLa cells and murine embryonic stem cells caused numerous spontaneous chromosome breaks. Furthermore, the phenotype of Xpf-deficient DT40 cells was reversed by ectopic expression of human Mus81-Eme1 or human Xpf-Ercc1 heterodimers. These observations indicate the functional overlap of Xpf-Ercc1 and Mus81-Eme1 in the maintenance of genomic DNA. Both Mus81-Eme1 and Xpf-Ercc1 contribute to the completion of HR, as evidenced by the data that the expression of Mus81-Eme1 or Xpf-Ercc1 diminished the number of camptothecin-induced chromosome breaks in Xpf-deficient DT40 cells, and to preventing early steps in HR by deleting XRCC3 suppressed the nonviability of Xpf-deficient DT40 cells. In summary, Xpf and Mus81 have a substantially overlapping function in completion of HR.
AB - DNA double-strand breaks (DSB) occur frequently during replication in sister chromatids and are dramatically increased when cells are exposed to chemotherapeutic agents including camptothecin. Such DSBs are efficiently repaired specifically by homologous recombination (HR) with the intact sister chromatid. HR, therefore, plays pivotal roles in cellular proliferation and cellular tolerance to camptothecin. Mammalian cells carry several structure-specific endonucleases, such as Xpf-Ercc1 and Mus81-Eme1, in which Xpf and Mus81 are the essential subunits for enzymatic activity. Here, we show the functional overlap between Xpf and Mus81 by conditionally inactivating Xpf in the chicken DT40 cell line, which has no Mus81 ortholog. Although mammalian cells deficient in either Xpf or Mus81 are viable, Xpf inactivation in DT40 cells was lethal, resulting in a marked increase in the number of spontaneous chromosome breaks. Similarly, inactivation of both Xpf and Mus81 in human HeLa cells and murine embryonic stem cells caused numerous spontaneous chromosome breaks. Furthermore, the phenotype of Xpf-deficient DT40 cells was reversed by ectopic expression of human Mus81-Eme1 or human Xpf-Ercc1 heterodimers. These observations indicate the functional overlap of Xpf-Ercc1 and Mus81-Eme1 in the maintenance of genomic DNA. Both Mus81-Eme1 and Xpf-Ercc1 contribute to the completion of HR, as evidenced by the data that the expression of Mus81-Eme1 or Xpf-Ercc1 diminished the number of camptothecin-induced chromosome breaks in Xpf-deficient DT40 cells, and to preventing early steps in HR by deleting XRCC3 suppressed the nonviability of Xpf-deficient DT40 cells. In summary, Xpf and Mus81 have a substantially overlapping function in completion of HR.
UR - http://www.scopus.com/inward/record.url?scp=84880882023&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84880882023&partnerID=8YFLogxK
U2 - 10.1158/0008-5472.CAN-12-3154
DO - 10.1158/0008-5472.CAN-12-3154
M3 - Article
C2 - 23576554
AN - SCOPUS:84880882023
SN - 0008-5472
VL - 73
SP - 4362
EP - 4371
JO - Cancer Research
JF - Cancer Research
IS - 14
ER -