RAD18 and RAD54 cooperatively contribute to maintenance of genomic stability in vertebrate cells.
Translesion DNA synthesis (TLS) and homologous DNA recombination (HR) are two major pathways that account for survival after post-replicational DNA damage. TLS functions by filling gaps on a daughter strand that remain after DNA replication caused by damage on the mother strand, while HR can repair gaps and breaks using the intact sister chromatid as a template. The RAD18 gene, which is conserved from lower eukaryotes to vertebrates, is essential for TLS in Saccharomyces cerevisiae. To investigate the role of RAD18, we disrupted RAD18 by gene targeting in the chicken B-lymphocyte line DT40. RAD18(-/-) cells are sensitive to various DNA-damaging agents including ultraviolet light and the cross-linking agent cisplatin, consistent with its role in TLS. Interestingly, elevated sister chromatid exchange, which reflects HR- mediated post-replicational repair, was observed in RAD18(-/-) cells during the cell cycle. Strikingly, double mutants of RAD18 and RAD54, a gene involved in HR, are synthetic lethal, although the single mutant in either gene can proliferate with nearly normal kinetics. These data suggest that RAD18 plays an essential role in maintaining chromosomal DNA in cooperation with the RAD54-dependent DNA repair pathway.
Yamashita
Yukiko M
YM
Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
Okada
Takashi
T
Matsusaka
Takahiro
T
Sonoda
Eiichiro
E
Zhao
Guang Yu
GY
Araki
Kasumi
K
Tateishi
Satoshi
S
Yamaizumi
Masaru
M
Takeda
Shunichi
S
D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002645:Chickens; D002945:Cisplatin / Q000633:toxicity; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics / Q000502:physiology*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D018390:Gene Targeting; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012854:Sister Chromatid Exchange; D044767:Ubiquitin-Protein Ligases; D014466:Ultraviolet Rays / Q000009:adverse effects
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C485954:RAD18 protein, human; D044767:Ubiquitin-Protein Ligases; D002945:Cisplatin