Tdp1 processes chromate-induced single-strand DNA breaks that collapse replication forks

• Published in: PLoS genetics Vol. 14; no. 8; p. e1007595
• Main Authors: Ganguly, Abantika, Guo, Lan, Sun, Lingling, Suo, Fang, Du, Li-Lin, Russell, Paul
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.08.2018; Public Library of Science (PLoS)
• Subjects: Arsenic; Base excision repair; Biology and Life Sciences; Cadmium; Camptothecin; Camptothecin - pharmacology; Cell cycle; Cell Cycle - drug effects; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Checkpoint Kinase 1 - genetics; Checkpoint Kinase 2 - drug effects; Chromate; Chromates - toxicity; Chromatids - metabolism; Chromium; Contamination; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA Breaks, Single-Stranded; DNA damage; DNA Repair - drug effects; DNA Replication; DNA Topoisomerases, Type I - genetics; DNA Topoisomerases, Type I - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drug Resistance, Fungal; Endonuclease; Endonucleases - genetics; Endonucleases - metabolism; ERCC1 protein; Genes; Genomes; Humans; Methods; Mutagenesis; Neurodegeneration; Neurodegenerative diseases; Nucleotide excision repair; Ontology; Phosphodiesterase; Phosphoric Diester Hydrolases - genetics; Phosphoric Diester Hydrolases - metabolism; Physical Sciences; Polynucleotide 5'-Hydroxyl-Kinase - genetics; Polynucleotide 5'-Hydroxyl-Kinase - metabolism; Polynucleotide kinase; Post-replication; Prevention; Proteins; Recombination; Replication forks; Research and Analysis Methods; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe Proteins - drug effects; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; Toxicity; Yeast; Beijing China; La Jolla California; California; United States > US; China
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1007595

Hexavalent chromium [Cr(VI)] damages DNA and causes cancer, but it is unclear which DNA damage responses (DDRs) most critically protect cells from chromate toxicity. Here, genome-wide quantitative functional profiling, DDR measurements and genetic interaction assays in Schizosaccharomyces pombe reveal a chromate toxicogenomic profile that closely resembles the cancer chemotherapeutic drug camptothecin (CPT), which traps Topoisomerase 1 (Top1)-DNA covalent complex (Top1cc) at the 3' end of single-stand breaks (SSBs), resulting in replication fork collapse. ATR/Rad3-dependent checkpoints that detect stalled and collapsed replication forks are crucial in Cr(VI)-treated cells, as is Mus81-dependent sister chromatid recombination (SCR) that repairs single-ended double-strand breaks (seDSBs) at broken replication forks. Surprisingly, chromate resistance does not require base excision repair (BER) or interstrand crosslink (ICL) repair, nor does co-elimination of XPA-dependent nucleotide excision repair (NER) and Rad18-mediated post-replication repair (PRR) confer chromate sensitivity in fission yeast. However, co-elimination of Tdp1 tyrosyl-DNA phosphodiesterase and Rad16-Swi10 (XPF-ERCC1) NER endonuclease synergistically enhances chromate toxicity in top1Δ cells. Pnk1 polynucleotide kinase phosphatase (PNKP), which restores 3'-hydroxyl ends to SSBs processed by Tdp1, is also critical for chromate resistance. Loss of Tdp1 ameliorates pnk1Δ chromate sensitivity while enhancing the requirement for Mus81. Thus, Tdp1 and PNKP, which prevent neurodegeneration in humans, repair an important class of Cr-induced SSBs that collapse replication forks.