About the Authors

Pamela Kanellis

Affiliations Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada , Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada

Mark Gagliardi

Affiliation Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada

Judit P Banath

Affiliation British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada

Rachel K Szilard

Affiliation Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada

Shinichiro Nakada

Affiliation Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada

Sarah Galicia

Affiliation Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada

Frederic D Sweeney

Affiliations Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada , Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada

Diane C Cabelof

Affiliation Karmanos Cancer Institute, Detroit, Michigan, United States of America

Peggy L Olive

Affiliation British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada

Daniel Durocher

To whom correspondence should be addressed. E-mail: durocher@mshri.on.ca

Affiliations Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada , Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

PK and DD conceived and designed the experiments, except for the FACS analysis of γ-H2AX, which was designed by PLO, and uracil quantitation, which was designed with DCC. PK performed all the yeast-related experiments except for the examination of Rad53 activity, which was done with the help of FDS. MG examined the formation of 53BP1 foci in response to 4-DP and examined the activation of the checkpoint response by Western blotting. JB quantitated γ-H2AX formation by flow cytometry. RKS mapped the breakpoints by CGH. SN examined the levels of apoptosis in response to 4-DP. SG performed some of the GCR assays. DCC determined uracil content in genomic DNA. PK and DD wrote the paper with valued input from RKS, DCC, and PLO.