Open AccessTrapped topoisomerase II initiates formation of de novo duplications via the nonhomologous end-joining pathway in yeast
Author(s) -
Nicole Stantial,
Anna Rogojina,
Matthew Gilbertson,
Yilun Sun,
Hannah N. Miles,
Samantha Shaltz,
James M. Berger,
Karin C. Nitiss,
Sue Jinks-Robertson,
John L. Nitiss
Publication year - 2020
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2008721117
Subject(s) - non homologous end joining , topoisomerase , dna , biology , mutant , dna ligase , dna replication , cleavage (geology) , dna repair , microbiology and biotechnology , yeast , dna damage , saccharomyces cerevisiae , genetics , gene , paleontology , fracture (geology)
Topoisomerase II (Top2) is an essential enzyme that resolves catenanes between sister chromatids as well as supercoils associated with the over- or under-winding of duplex DNA. Top2 alters DNA topology by making a double-strand break (DSB) in DNA and passing an intact duplex through the break. Each component monomer of the Top2 homodimer nicks one of the DNA strands and forms a covalent phosphotyrosyl bond with the 5' end. Stabilization of this intermediate by chemotherapeutic drugs such as etoposide leads to persistent and potentially toxic DSBs. We describe the isolation of a yeast top2 mutant ( top2-F1025Y,R1128G ) the product of which generates a stabilized cleavage intermediate in vitro. In yeast cells, overexpression of the top2-F1025Y,R1128G allele is associated with a mutation signature that is characterized by de novo duplications of DNA sequence that depend on the nonhomologous end-joining pathway of DSB repair. Top2-associated duplications are promoted by the clean removal of the enzyme from DNA ends and are suppressed when the protein is removed as part of an oligonucleotide. TOP2 cells treated with etoposide exhibit the same mutation signature, as do cells that overexpress the wild-type protein. These results have implications for genome evolution and are relevant to the clinical use of chemotherapeutic drugs that target Top2.