TY - JOUR
T1 - DNA lesion identity drives choice of damage tolerance pathway in murine cell chromosomes
AU - Cohen, Isadora S.
AU - Bar, Carmit
AU - Paz-Elizur, Tamar
AU - Ainbinder, Elena
AU - Leopold, Karoline
AU - De Wind, Niels
AU - Geacintov, Nicholas
AU - Livneh, Zvi
N1 - Publisher Copyright:
© The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
PY - 2015/2/18
Y1 - 2015/2/18
N2 - DNA-damage tolerance (DDT) via translesion DNA synthesis (TLS) or homology-dependent repair (HDR) functions to bypass DNA lesions encountered during replication, and is critical for maintaining genome stability. Here, we present piggyBlock, a new chromosomal assay that, using piggyBac transposition of DNA containing a known lesion, measures the division of labor between the two DDT pathways. We show that in the absence of DNA damage response, tolerance of the most common sunlight-induced DNA lesion, TT-CPD, is achieved by TLS in mouse embryo fibroblasts. Meanwhile, BP-G, a major smoke-induced DNA lesion, is bypassed primarily by HDR, providing the first evidence for this mechanism being the main tolerance pathway for a biologically important lesion in a mammalian genome. We also show that, far from being a last-resort strategy as it is sometimes portrayed, TLS operates alongside nucleotide excision repair, handling 40% of TT-CPDs in repair-proficient cells. Finally, DDT acts in mouse embryonic stem cells, exhibiting the same pattern - mutagenic TLS included - despite the risk of propagating mutations along all cell lineages. The new method highlights the importance of HDR, and provides an effective tool for studying DDT in mammalian cells.
AB - DNA-damage tolerance (DDT) via translesion DNA synthesis (TLS) or homology-dependent repair (HDR) functions to bypass DNA lesions encountered during replication, and is critical for maintaining genome stability. Here, we present piggyBlock, a new chromosomal assay that, using piggyBac transposition of DNA containing a known lesion, measures the division of labor between the two DDT pathways. We show that in the absence of DNA damage response, tolerance of the most common sunlight-induced DNA lesion, TT-CPD, is achieved by TLS in mouse embryo fibroblasts. Meanwhile, BP-G, a major smoke-induced DNA lesion, is bypassed primarily by HDR, providing the first evidence for this mechanism being the main tolerance pathway for a biologically important lesion in a mammalian genome. We also show that, far from being a last-resort strategy as it is sometimes portrayed, TLS operates alongside nucleotide excision repair, handling 40% of TT-CPDs in repair-proficient cells. Finally, DDT acts in mouse embryonic stem cells, exhibiting the same pattern - mutagenic TLS included - despite the risk of propagating mutations along all cell lineages. The new method highlights the importance of HDR, and provides an effective tool for studying DDT in mammalian cells.
UR - https://www.scopus.com/pages/publications/84936791804
U2 - 10.1093/nar/gku1398
DO - 10.1093/nar/gku1398
M3 - Article
C2 - 25589543
AN - SCOPUS:84936791804
SN - 0305-1048
VL - 43
SP - 1637
EP - 1645
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 3
ER -