RRC ID 53344
Author van Schendel R, van Heteren J, Welten R, Tijsterman M.
Title Genomic Scars Generated by Polymerase Theta Reveal the Versatile Mechanism of Alternative End-Joining.
Journal PLoS Genet
Abstract For more than half a century, genotoxic agents have been used to induce mutations in the genome of model organisms to establish genotype-phenotype relationships. While inaccurate replication across damaged bases can explain the formation of single nucleotide variants, it remained unknown how DNA damage induces more severe genomic alterations. Here, we demonstrate for two of the most widely used mutagens, i.e. ethyl methanesulfonate (EMS) and photo-activated trimethylpsoralen (UV/TMP), that deletion mutagenesis is the result of polymerase Theta (POLQ)-mediated end joining (TMEJ) of double strand breaks (DSBs). This discovery allowed us to survey many thousands of available C. elegans deletion alleles to address the biology of this alternative end-joining repair mechanism. Analysis of ~7,000 deletion breakpoints and their cognate junctions reveals a distinct order of events. We found that nascent strands blocked at sites of DNA damage can engage in one or more cycles of primer extension using a more downstream located break end as a template. Resolution is accomplished when 3' overhangs have matching ends. Our study provides a step-wise and versatile model for the in vivo mechanism of POLQ action, which explains the molecular nature of mutagen-induced deletion alleles.
Volume 12(10)
Pages e1006368
Published 2016-10-1
DOI 10.1371/journal.pgen.1006368
PMID 27755535
PMC PMC5068794
MeSH Animals Caenorhabditis elegans / drug effects Caenorhabditis elegans / genetics* DNA Breaks, Double-Stranded / drug effects DNA End-Joining Repair / genetics* DNA Polymerase theta DNA Repair / drug effects* DNA Repair / genetics DNA Replication / drug effects DNA-Directed DNA Polymerase / biosynthesis DNA-Directed DNA Polymerase / genetics* Ethyl Methanesulfonate / toxicity Genetic Association Studies Genome / drug effects Mutagenesis Mutagens / toxicity Sequence Deletion / drug effects
IF 5.175
Times Cited 16
C.elegans tm2026 tm1298