Evidence for DNA Cleavage Caused Directly by a Transfer RNA-targeting Toxin

PLoS One. 2013 Sep 17;8(9):e75512. doi: 10.1371/journal.pone.0075512. eCollection 2013.


The killer yeast species Pichiaacaciae produces a heteromeric killer protein, PaT, that causes DNA damage and arrests the cell cycle of sensitive Saccharomyces cerevisiae in the S phase. However, the mechanism by which DNA damage occurs remains elusive. A previous study has indicated that Orf2p, a subunit of PaT, specifically cleaves an anticodon loop of an S. cerevisiae transfer RNA (tRNA(Gln)mcm5s2UUG). This finding raised a question about whether the DNA damage is a result of the tRNA cleavage or whether Orf2p directly associates with and cleaves the genomic DNA of sensitive yeast cells. We showed that Orf2p cleaves genomic DNA in addition to cleaving tRNA in vitro. This DNA cleavage requires the same Orf2p residue as that needed for tRNA cleavage, His299. The expression of Orf2p, in which His299 was substituted to alanine, abolished the cell cycle arrest of the host cell. Moreover, the translation impairment induced by tRNA cleavage enabled Orf2p to enter the nucleus, thereby inducing histone phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Checkpoints
  • Cell Nucleus / metabolism
  • DNA Cleavage*
  • DNA Damage
  • Histones / metabolism
  • Killer Factors, Yeast / metabolism*
  • Phosphorylation
  • Protein Biosynthesis
  • Protein Transport
  • RNA, Transfer / genetics*
  • RNA, Transfer / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / metabolism


  • Histones
  • Killer Factors, Yeast
  • Saccharomyces cerevisiae Proteins
  • RNA, Transfer

Grant support

This work was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (No.21658029, HM), and by Takeda Science Foundation to TO. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.