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

Abstract
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.