The N-terminal half of NPM dissociates from nucleoli of HeLa cells after anticancer drug treatments

Biochem Biophys Res Commun. 1999 Oct 14;264(1):305-9. doi: 10.1006/bbrc.1999.1255.


NPM (nucleophosmin/B23) is a nucleolar phosphoprotein abundant in tumor cells. It dissociates from nucleoli of cells after treatments with various anticancer drugs. To determine the domain of NPM responsible for nucleolar binding, the N- and C-terminal halves of NPM were fused to GFP (green fluorescent protein) and introduced into HeLa cells. The N-terminal half (aa 1-150) of NPM (GFP-NPM(N)) was found localized in the nucleoli. A stable transformant of GFP-NPM(N) in HeLa cells was prepared and tested for association to nucleoli after anticancer drug treatments. GFP-NPM(N) dissociates from nucleoli after treatments with daunomycin, actinomycin D, camptothecin, and toyocamycin. The dissociation is time- and dose-dependent, and correlates with the cytotoxicity induced by the drugs. These results indicate that a stable transformant of GFP-NPM(N) in HeLa cells may be useful for the screening of anticancer drugs.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Biological Transport
  • Cell Nucleolus / drug effects*
  • Cell Nucleolus / metabolism
  • Cell Nucleolus / pathology
  • Drug Screening Assays, Antitumor
  • Green Fluorescent Proteins
  • HeLa Cells
  • Humans
  • Luminescent Proteins / metabolism
  • Nuclear Proteins / drug effects
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Nucleophosmin


  • Antineoplastic Agents
  • Luminescent Proteins
  • NPM1 protein, human
  • Nuclear Proteins
  • Nucleophosmin
  • Green Fluorescent Proteins