Appropriately spaced nuclear localizing signals are necessary for efficient nuclear import of nonnuclear proteins

Harm Jan W. Borgeld, Keiji Naruse, Shuh Ichi Nishikawa, Jin Zhang, Akihiko Kikuchi, Koichi Furukawa, Kunio Yagi, Masashi Tanaka

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2 Citations (Scopus)


To deliver nonnuclear proteins into the nucleus, we have examined the locations and number of nuclear localizing signals by use of simian virus 40 large T-antigen (SV40Ta) and yeast enhanced green fluorescent protein (yEGFP) in Saccharomyces cerevisiae as a model system. When only one SV40Ta was added to either the N- or C-terminus of yEGFP, the fluorescence of yEGFP was detected in both the nucleus and the cytoplasm. When two SV40Ta signals were added, one to the N-terminus and one to the C-terminus of yEGFP (SV40Ta-yEGFP-SV40Ta), the fluorescence of yEGFP was localized in only the nucleus. When the presequence of cytochrome oxidase subunit IV (pCOXIV) was inserted between the SV40Ta and the N-terminus of yEGFP (SV40Ta-pCOXIV-yEGFP-SV40Ta) in this construct, the fluorescence was located in both the nucleus and the cytoplasm, suggesting that the increased distance between the two SV40Ta signals decreased the efficiency of transport into the nucleus. When an additional SV40Ta signal was inserted between pCOXIV and yEGFP (SV40Ta-pCOXIV-SV40Ta-yEGFP), the fluorescence was localized only in the nucleus, indicating that two SV40Ta signals spaced by pCOXIV of 28 amino acid residues forming an α-helix are potent in transporting yEGFP into the nucleus. These results indicate that two SV40Ta signals spaced appropriately are essential for the efficient transport of the nonnuclear protein into the nucleus.

Original languageEnglish
Pages (from-to)278-283
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - Mar 16 1999



  • Nuclear import
  • Nuclear localizing signal
  • Saccharomyces cerevisiae
  • Yeast enhanced green fluorescent protein

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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