Characterization of a poplar NIMA-related kinase PNek1 and its potential role in meristematic activity

Meristems are sites of undifferentiated cell division, which carry on developing into functional organs. Using the two-hybrid system with a poplar 14-3-3, we uncovered poplar NIMA-related kinase 1 (PNek1) as an interacting protein. PNek1 shows high homology to the mammalian NIMA-related kinases, which are thought to be involved in cell cycle progression. Using a synchronized poplar cell suspension, we observed an accumulation of PNek1 mRNA at the G1/S transition and throughout the G2-to-M progression. Moreover, PNek1-GFP fusion protein localized in the cytoplasm and in both the nuclear and nucleolar regions. Overexpression of PNek1-GFP in Arabidopsis caused morphological abnormalities in flower and siliques. Overall, these results suggest that PNek1 is involved in plant development.