Screening of nuclear targeting proteins in Acinetobacter baumannii based on nuclear localization signals

Res Microbiol. 2012 May;163(4):279-85. doi: 10.1016/j.resmic.2012.02.001. Epub 2012 Feb 14.


Nuclear targeting of bacterial proteins is an emerging pathogenic mechanism in bacteria. However, due to the absence of an appropriate screening system for nuclear targeting proteins, systematic approaches to nuclear targeting of bacterial proteins and subsequent host cell pathology are limited. In this study, we developed a screening system for nuclear targeting proteins in Acinetobacter baumannii using a combination of bioinformatic analysis based on nuclear localization signal (NLS) and the Gateway(®) recombinational cloning system. Among 3367 open reading frames of A. baumannii ATCC 17978, 34 functional or hypothetical proteins were predicted to carry the putative NLS sequences. Of the 29 clones generated by the Gateway(®) recombinational cloning system, 14 proteins tagged with green fluorescent protein (GFP) were targeted to nuclei of host cells. Among the 14 nuclear targeting proteins, S21, L20, and L32 ribosomal proteins and transposase carried putative nuclear export signal (NES) sequences, but only transposase harbored the functional NES. After translocation to nuclei of host cells, four A. baumannii proteins induced cytotoxicity. In conclusion, we have developed a screening system for nuclear targeting proteins in A. baumannii. This system may open the way to a new field of bacterial pathogenesis.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter baumannii / chemistry
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / metabolism*
  • Animals
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacteriological Techniques / methods*
  • COS Cells
  • Cell Line
  • Chlorocebus aethiops
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Molecular Sequence Data
  • Nuclear Localization Signals*
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Protein Transport
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism


  • Bacterial Proteins
  • Nuclear Localization Signals
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins