title: Yeast Tdp1 and Rad1-Rad10 function as redundant pathways for repairing Top1 replicative damage.
abstract: When a replication fork collides with a DNA topoisomerase I (Top1) cleavage complex, the covalently bound enzyme must be removed from the DNA 3' end before recombination-dependent replication restart. Here we report that the tyrosyl-DNA phosphodiesterase Tdp1 and the structure-specific endonuclease Rad1-Rad10 function as primary alternative pathways of Top1 repair in Saccharomyces cerevisiae. Thus, tdp1 rad1 cells (including the catalytic point mutant rad1-D869A) not only are highly sensitive to the Top1 poison camptothecin but also exhibit a TOP1-dependent growth delay. Extensive genetic analysis revealed that both Tdp1 and Rad1-Rad10 repair proceed through recombination that equally depends on RAD52, RAD51, and RAD50. The Rad1-Rad10 pathway further particularly depends on RAD59 and SRS2 but is independent of other nucleotide excision repair genes. Although this pattern is consistent with Rad1-Rad10 removing Top1 in a manner similar to its removal of nonhomologous tails during gene conversion, these differ in that Top1 removal does not require Msh2-Msh3. Finally, we show that yeast lacking the Rad1-Rad10-related proteins Mus81-Mms4 display a unique pattern of camptothecin sensitivity and suggest a concerted model for the action of these endonucleases.
mesh_terms: D002166:Camptothecin / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics; D045643:DNA Repair Enzymes; D004261:DNA Replication; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D045585:Flap Endonucleases; D005656:Fungal Proteins / Q000378:metabolism*; D005800:Genes, Fungal; D008954:Models, Biological; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D015719:Single-Strand Specific DNA and RNA Endonucleases; D059004:Topoisomerase I Inhibitors; D015534:Trans-Activators / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D059004:Topoisomerase I Inhibitors; D015534:Trans-Activators; D004720:Endonucleases; D045585:Flap Endonucleases; C411624:MUS81 protein, S cerevisiae; C069266:RAD1 protein, S cerevisiae; C112337:MMS4 protein, S cerevisiae; C064162:RAD10 protein, S cerevisiae; D015719:Single-Strand Specific DNA and RNA Endonucleases; D010727:Phosphoric Diester Hydrolases; C122147:tyrosyl-DNA phosphodiesterase; D004264:DNA Topoisomerases, Type I; D045643:DNA Repair Enzymes; D002166:Camptothecin