DNA polymerase eta (Pol eta) is a member of the mammalian Y family polymerases and performs error-free translesion synthesis across UV-damaged DNA. For this function, Pol eta accumulates in nuclear foci at replication stalling sites via its interaction with monoubiquitinated PCNA. However, little is known about the posttranslational control mechanisms of Pol eta, which regulate its accumulation in replication foci. Here, we report that the molecular chaperone Hsp90 promotes UV irradiation-induced nuclear focus formation of Pol eta through control of its stability and binding to monoubiquitinated PCNA. Our data indicate that Hsp90 facilitates the folding of Pol eta into an active form in which PCNA- and ubiquitin-binding regions are functional. Furthermore, Hsp90 inhibition potentiates UV-induced cytotoxicity and mutagenesis in a Pol eta-dependent manner. Our studies identify Hsp90 as an essential regulator of Pol eta-mediated translesion synthesis.
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http://dx.doi.org/10.1016/j.molcel.2009.12.015 | DOI Listing |
Int J Mol Sci
January 2025
Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia.
The apurinic/apyrimidinic site (AP site) is a highly mutagenic and cytotoxic DNA lesion. Normally, AP sites are removed from DNA by base excision repair (BER). Methoxyamine (MOX), a BER inhibitor currently under clinical trials as a tumor sensitizer, forms adducts with AP sites (AP-MOX) resistant to the key BER enzyme, AP endonuclease.
View Article and Find Full Text PDFThe 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.
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