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Nat Commun. 2015 Dec 17;6:10260. doi: 10.1038/ncomms10260.

T7 replisome directly overcomes DNA damage.

Author information

1
Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
2
Howard Hughes Medical Institute, Cornell University, Ithaca, New York 14853, USA.
3
School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
4
Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
5
NCI Center for Cancer Research, Frederick, Maryland 21702, USA.

Abstract

Cells and viruses possess several known 'restart' pathways to overcome lesions during DNA replication. However, these 'bypass' pathways leave a gap in replicated DNA or require recruitment of accessory proteins, resulting in significant delays to fork movement or even cell division arrest. Using single-molecule and ensemble methods, we demonstrate that the bacteriophage T7 replisome is able to directly replicate through a leading-strand cyclobutane pyrimidine dimer (CPD) lesion. We show that when a replisome encounters the lesion, a substantial fraction of DNA polymerase (DNAP) and helicase stay together at the lesion, the replisome does not dissociate and the helicase does not move forward on its own. The DNAP is able to directly replicate through the lesion by working in conjunction with helicase through specific helicase-DNAP interactions. These observations suggest that the T7 replisome is fundamentally permissive of DNA lesions via pathways that do not require fork adjustment or replisome reassembly.

PMID:
26675048
PMCID:
PMC4703881
DOI:
10.1038/ncomms10260
[Indexed for MEDLINE]
Free PMC Article

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