Replication through (6-4)TT and G-AAF lesions was compared in Saccharomyces cerevisiae strains proficient and deficient for the RAD30-encoded DNA polymerase eta (Pol eta). In the RAD30 strain, the (6-4)TT lesion is replicated both inaccurately and accurately 60 and 40% of the time, respectively. Surprisingly, in a rad30 Delta strain, the level of mutagenic bypass is essentially suppressed, while error-free bypass remains unchanged. Therefore, Pol eta is responsible for mutagenic replication through the (6-4)TT photoproduct, while another polymerase mediates its error-free bypass. Deletion of the RAD30 gene also reduces the levels of both accurate and inaccurate bypass of AAF lesions within two different sequence contexts up to 8-fold. These data show that, in contrast to the accurate bypass by Pol eta of TT cyclobutane dimers, it is responsible for the mutagenic bypass of other lesions. In conclusion, this paper shows that, in yeast, translesion synthesis involves the combined action of several polymerases.
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http://dx.doi.org/10.1093/emboj/cdf363 | DOI Listing |
The replicative polymerase delta is inefficient copying repetitive DNA sequences. Error-prone translesion polymerases have been shown to switch with high-fidelity replicative polymerases to help navigate repetitive DNA. We and others have demonstrated the importance of one such translesion polymerase, polymerase Eta (pol eta), in facilitating replication at genomic regions called common fragile sites (CFS), which are difficult-to-replicate genomic regions that are hypersensitive to replication stress.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA.
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, 05405, USA.
8-oxoguanine (8-oxoG) is a common oxidative DNA lesion that causes G > T substitutions. Determinants of local and regional differences in 8-oxoG-induced mutability across genomes are currently unknown. Here, we show DNA oxidation induces G > T substitutions and insertion/deletion (INDEL) mutations in human cells and cancers.
View Article and Find Full Text PDFFront Physiol
November 2024
Department of Intervention Research in Exercise Training, German Sport University Cologne, Cologne, Germany.
Purpose: High-intensity functional interval training (HIFT) is predominantly composed of high exercise training intensities (HiT) and loads. Both have been linked to a higher risk of overtraining and injuries in inexperienced populations. A polarized training approach is characterized by high amounts of low-intensity training (LiT) and only approximately 5%-20% HiT.
View Article and Find Full Text PDFCells
October 2024
Institute for Molecular Biology II, Center of Medical Biotechnology (ZMB), University of Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany.
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