A functional genetic assay for nuclear trafficking in plants

Thirumala Devi Kanneganti, Xiaodong Bai, Chi Wei Tsai, Joe Win, Tea Meulia, Michael Goodin, Sophien Kamoun, Saskia A. Hogenhout

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

The receptor importin-α mediates the nuclear import of functionally diverse cargo proteins that contain arginine/lysine-rich nuclear localization signals (NLSs). Functional homologs of importin-α have been characterized in a wide range of species including yeast, human and plants. However, the differential cargo selectivity of plant importin-α homologs has not been established. To advance nuclear import studies conducted in plant cells, we have developed a method that allows importin-α-dependent nuclear import to be assayed in Nicotiana benthamiana. We employed virus-induced gene silencing (VIGS) to knock down the expression of two importin-α homologs, NbImpα1 and NbImpα2, which we identified from N. benthamiana. Agro-infiltration was then used to transiently express the NLS-containing proteins Arabidopsis thaliana fibrillarin 1 (AtFib1) and the Nuk6, Nuk7 and Nuk12 candidate effector proteins of the oomycete plant pathogen Phytophthora infestans. In this manner, we demonstrate importin-α-dependent nuclear import of Nuk6 and Nuk7. In contrast, the nuclear import of Nuk12 and AtFib1 was unaffected in cells of NbImpα-silenced plants. These data suggest that P. infestans Nuk6 and Nuk7 proteins are dependent on one or more α-importins for nuclear import. Our VIGS-based assay represents a powerful new technique to study mechanisms underlying the transport of proteins from cytoplasm to nucleus in plants.

Original languageEnglish
Pages (from-to)149-158
Number of pages10
JournalPlant Journal
Volume50
Issue number1
DOIs
StatePublished - Apr 2007

Keywords

  • Agro-infiltration
  • Importin-α
  • Nuclear import
  • Plant pathogen
  • VIGS

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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