Identification and characterization of the Arabidopsis FG-repeat nucleoporin Nup62

Ran is a multifunctional small GTPase that is involved in nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope reformation. Nuclear transport factor 2 (NTF2) facilitates nuclear import of Ran. It binds FxFG repeatcontaining domains of the nucleoporins Nup62 (vertebrate) and Nsp1p (yeast). Here, we have identified Arabidopsis Nup62 through its sequence similarity to mammalian Nup62 and yeast Nsp1p. A GFP-AtNup62 fusion protein is associated with the nuclear envelope in transgenic Arabidopsis plants and interacts in planta with AtNTF2a, one of the two Arabidopsis NTF2 homologs. Overexpression-based co-suppression of AtNup62 leads to severely dwarfed, early-flowering plants, suggesting an important function for Nup62 in plants.