Selective transport of cationized fluorescent topoisomerase into nuclei of live cells for DNA damage studies

Methods Mol Biol. 2014;1094:167-75. doi: 10.1007/978-1-62703-706-8_14.


The targeted delivery of fluorescently labeled, DNA-modifying proteins into cellular nuclei permits investigation of DNA damage and chromatin function in living cells. Commercially available protein delivery vectors cannot provide selective intranuclear transportation and primarily unload their cargo in the cytoplasm. Here we describe a simple approach for specific intranuclear transportation of vaccinia topoisomerase protein based on its cationization. The delivered protein can be observed and monitored by fluorescence microscopy. The technique is cost-efficient and time-saving. It can be useful in live cell studies.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, N.I.H., Extramural

MeSH terms

  • Anions
  • Cations
  • Cell Line, Tumor
  • Cell Nucleus / enzymology*
  • Cell Survival
  • DNA Damage*
  • DNA Topoisomerases, Type I / metabolism*
  • Humans
  • Microscopy, Fluorescence / methods*
  • Polyethyleneimine / chemistry
  • Protein Transport
  • Vaccinia virus / enzymology


  • Anions
  • Cations
  • Polyethyleneimine
  • DNA Topoisomerases, Type I