Unlike Catalyzing Error-Free Bypass of 8‑OxodGuo, DNA Polymerase λ Is Responsible for a Significant Part of Fapy·dG-Induced G → T Mutations in Human Cells

8-OxodGuo and Fapy·dG induced 10–22% mutations, predominantly G → T transversions, in human embryonic kidney 293T cells in four TG*N sequence contexts, where N = C, G, A, or T. siRNA knockdown of pol λ resulted in 34 and 55% increases in the level of mutations in the progeny from the 8-oxodGuo construct in the TG*T and TG*G sequences, respectively, suggesting that pol λ is involved in error-free bypass of 8-oxodGuo. For Fapy·dG, in contrast, the level of G → T mutations was reduced by 27 and 46% in the TG*T and TG*G sequences, respectively, suggesting that pol λ is responsible for a significant fraction of Fapy·dG-induced G → T mutations

Media 4: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 6: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Mutational Analysis of the C8-Guanine Adduct of the Environmental Carcinogen 3‑Nitrobenzanthrone in Human Cells: Critical Roles of DNA Polymerases η and κ and Rev1 in Error-Prone Translesion Synthesis

3-Nitrobenzanthrone (3-NBA), a potent mutagen and suspected human carcinogen, is a common environmental pollutant. The genotoxicity of 3-NBA has been associated with its ability to form DNA adducts, including <i>N</i>-(2′-deoxyguanosin-8-yl)-3-aminobenzanthrone (C8-dG-ABA). To investigate the molecular mechanism of C8-dG-ABA mutagenesis in human cells, we have replicated a plasmid containing a single C8-dG-ABA in human embryonic kidney 293T (HEK293T) cells, which yielded 14% mutant progeny. The major types of mutations induced by C8-dG-ABA were G → T > G → A > G → C. siRNA knockdown of the translesion synthesis (TLS) DNA polymerases (pols) in HEK293T cells indicated that pol η, pol κ, pol ι, pol ζ, and Rev1 each have a role in replication across this adduct. The extent of TLS was reduced with each pol knockdown, but the largest decrease (of ∼55% reduction) in the level of TLS occurred in cells with knockdown of pol ζ. Pol η and pol κ were considered the major contributors of the mutagenic TLS, because the mutation frequency (MF) decreased by 70%, when these pols were simultaneously knocked down. Rev1 also is important for mutagenesis, as reflected by the 60% reduction in MF upon Rev1 knockdown, but it probably plays a noncatalytic role by physically interacting with the other two Y-family pols. In contrast, pol ζ appeared to be involved in the error-free bypass of the lesion, because MF increased by 60% in pol ζ knockdown cells. These results provide important mechanistic insight into the bypass of the C8-dG-ABA adduct

Media 2: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 1: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 3: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 9: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 5: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186

Media 8: A dual-modality optical coherence tomography and fluorescence lifetime imaging microscopy system for simultaneous morphological and biochemical tissue characterization

Originally published in Biomedical Optics Express on 02 August 2010 (boe-1-1-186