Mitochondrial tyrosyl-DNA phosphodiesterase 2 and its TDP2S short isoform

Shar yin N. Huang*, Ilaria Dalla Rosa, Stephanie A. Michaels, David V. Tulumello, Keli Agama, Salim Khiati, Sae Rin Jean, Simone A. Baechler, Valentina M. Factor, Sudhir Varma, Junko Murai, Lisa M. Miller Jenkins, Shana O. Kelley, Yves Pommier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Tyrosyl-DNA phosphodiesterase 2 (TDP2) repairs abortive topoisomerase II cleavage complexes. Here, we identify a novel short isoform of TDP2 (TDP2S) expressed from an alternative transcription start site. TDP2S contains a mitochondrial targeting sequence, contributing to its enrichment in the mitochondria and cytosol, while full-length TDP2 contains a nuclear localization signal and the ubiquitin-associated domain in the N-terminus. Our study reveals that both TDP2 isoforms are present and active in the mitochondria. Comparison of isogenic wild-type (WT) and TDP2 knockout (TDP2−/−/−) DT40 cells shows that TDP2−/−/− cells are hypersensitive to mitochondrial-targeted doxorubicin (mtDox), and that complementing TDP2−/−/− cells with human TDP2 restores resistance to mtDox. Furthermore, mtDox selectively depletes mitochondrial DNA in TDP2−/−/− cells. Using CRISPR-engineered human cells expressing only the TDP2S isoform, we show that TDP2S also protects human cells against mtDox. Finally, lack of TDP2 in the mitochondria reduces the mitochondria transcription levels in two different human cell lines. In addition to identifying a novel TDP2S isoform, our report demonstrates the presence and importance of both TDP2 isoforms in the mitochondria.

Original languageEnglish (US)
Article numbere42139
JournalEMBO Reports
Issue number3
StatePublished - Mar 2018
Externally publishedYes


  • DNA repair
  • mitochondria
  • mitochondrial DNA
  • topoisomerase

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Biochemistry


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