Translesion DNA synthesis across non-DNA segments in cultured human cells.

摘要: Abstract DNA lesions that have escaped repair are tolerated via translesion synthesis (TLS), carried out by specialized error-prone polymerases. To evaluate the robustness of TLS system in human cells, we examined its ability to cope with foreign non-DNA stretches 3 or 12 methylene residues, using a gap-lesion plasmid assay system. We found both trimethylene and dodecamethylene inserts were bypassed significant efficiencies misinsertion misalignment mechanisms. across these segments was aphidicolin-sensitive, did not require polη. In vitro primer extension assays showed purified polη, polκ polι each capable inserting four nucleotides opposite chain, but only polη could fully bypass it. Polη polι, polκ, also insert all three polymerases severely blocked this lesion. The hydrocarbon despite lack any similarity DNA, suggests they may act mode transient local template-independent polymerase activity, highlights cells.