title: [Identification of nucleolar localization signal sequence of tumor metastasis suppressor gene-1].
abstract: OBJECTIVE
  To identify the putative specific localization signal sequence of tumor metastasis suppressor gene-1 (TMSG-1) and to explore the mechanism of subcellular localization of TMSG-1 protein.
  
  
  METHODS
  Vectors expressing green fluorescence protein (GFP) tagged different TMSG-1 fragments were generated and transfected into human embryo kidney 293 (HEK293) cells. The expression of those fusion proteins was detected by Western blotting and their subcellular localizations were observed by laser confocal microscope.
  
  
  RESULTS
  GFP was fused with the native TMSG-1(aa1-380) or different fragments including T1 (aa1-70), T2 (aa1-128), T3 (aa129-380), T4 (aa71-128), T5 (aa71-179) and T6 (aa71-380). Anti-GFP Western blotting showed that these fusion proteins were successfully expressed. Under laser confocal microscope, GFP fused with fragment T4 (aa71-128) localized mainly in the nucleolus; GFP fused with fragment T6 (aa71-380) localized diffusely in the nucleus; while other fusion proteins with TMSG-1 (aa1-380) or fragment T1 (aa1-70), T2 (aa1-128), T3 (aa129-380) and T5 (aa71-179) localized in the cytoplasm. Fragment T4(Δ119-128) was generated from T4 with deletion of 10 amino acid of the C terminal. GFP fused with fragment T4(Δ119-128) remained in the nucleus, but no longer in the nucleolus.
  
  
  CONCLUSIONS
  There is a nucleolar localization signal (aa119-128 RRRRNQDRPS) within TMSG-1. This finding may have laid the foundation for further investigations into subcellular localization and function of TMSG-1.
authors.affiliation: Department of Pathology, Health Science Center, Peking University, Beijing 100191, China.
authors.forename: Miao-zi
authors.initials: MZ
authors.lastname: Gong
authors.forename: Jiang-feng
authors.initials: JF
authors.lastname: You
authors.forename: Xiang-lin
authors.initials: XL
authors.lastname: Cui
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D019913:Nuclear Localization Signals; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051049:Sphingosine N-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D019913:Nuclear Localization Signals; D011993:Recombinant Fusion Proteins; D025521:Tumor Suppressor Proteins; D049452:Green Fluorescent Proteins; C438311:CERS2 protein, human; D051049:Sphingosine N-Acyltransferase