A critical role for the ubiquitin-conjugating enzyme Ubc13 in initiating homologous recombination.
The ubiquitin (Ub)-conjugating enzyme Ubc13 is implicated in Rad6/Rad18-dependent postreplication repair (PRR) in budding yeast, but its function in vertebrates is not known. We show here that disruption or siRNA depletion of UBC13 in chicken DT40 or human cells confers severe growth defects due to chromosome instability, and hypersensitivity to both UV and ionizing radiation, consistent with a conserved role for Ubc13 in PRR. Remarkably, Ubc13-deficient cells are also compromised for DNA double-strand break (DSB) repair by homologous recombination (HR). Recruitment and activation of the E3 Ub ligase function of BRCA1 and the subsequent formation of the Rad51 nucleoprotein filament at DSBs are abolished in Ubc13-deficient cells. Furthermore, generation of ssDNA/RPA complexes at DSBs is severely attenuated in the absence of Ubc13. These data reveal a critical and unexpected role for vertebrate Ubc13 in the initiation of HR at the level of DSB processing.
Zhao
Guang Yu
GY
CREST Laboratory, Department of Radiation Genetics, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
Sonoda
Eiichiro
E
Barber
Louise J
LJ
Oka
Hayato
H
Murakawa
Yasuhiro
Y
Yamada
Kouichi
K
Ikura
Tsuyoshi
T
Wang
Xin
X
Kobayashi
Masahiko
M
Yamamoto
Kenichi
K
Boulton
Simon J
SJ
Takeda
Shunichi
S
D000818:Animals; D019313:BRCA1 Protein / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000528:radiation effects; D002645:Chickens; D002875:Chromosomes / Q000187:drug effects / Q000528:radiation effects; D004247:DNA / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D005091:Exons / Q000235:genetics; D018390:Gene Targeting; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007259:Infrared Rays; D008957:Models, Genetic; D009153:Mutagens / Q000633:toxicity; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic / Q000187:drug effects / Q000528:radiation effects; D051716:Replication Protein A / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000172:deficiency / Q000378:metabolism*; D014466:Ultraviolet Rays
D019313:BRCA1 Protein; D006657:Histones; D009153:Mutagens; D051716:Replication Protein A; D025801:Ubiquitin; D004247:DNA; C471607:UBE2N protein, human; D044763:Ubiquitin-Conjugating Enzymes; D051135:Rad51 Recombinase