NLS-tagging: an alternative strategy to tag nuclear proteins

Nucleic Acids Res. 2014 Dec 1;42(21):e163. doi: 10.1093/nar/gku869. Epub 2014 Sep 26.


The characterization of transcription factor complexes and their binding sites in the genome by affinity purification has yielded tremendous new insights into how genes are regulated. The affinity purification requires either the use of antibodies raised against the factor of interest itself or by high-affinity binding of a C- or N-terminally added tag sequence to the factor. Unfortunately, fusing extra amino acids to the termini of a factor can interfere with its biological function or the tag may be inaccessible inside the protein. Here, we describe an effective solution to that problem by integrating the 'tag' close to the nuclear localization sequence domain of the factor. We demonstrate the effectiveness of this approach with the transcription factors Fli-1 and Irf2bp2, which cannot be tagged at their extremities without loss of function. This resulted in the identification of novel proteins partners and a new hypothesis on the contribution of Fli-1 to hematopoiesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation
  • Cell Line, Tumor
  • Nuclear Localization Signals*
  • Nuclear Proteins / analysis*
  • Nuclear Proteins / chemistry
  • Proto-Oncogene Protein c-fli-1 / analysis
  • Proto-Oncogene Protein c-fli-1 / chemistry
  • Proto-Oncogene Protein c-fli-1 / metabolism
  • Transcription Factors / analysis*
  • Transcription Factors / chemistry
  • Transcription Factors / metabolism


  • Nuclear Localization Signals
  • Nuclear Proteins
  • Proto-Oncogene Protein c-fli-1
  • Transcription Factors