Kinesin-related proteins containing armadillo repeats, ANTLERS1 and ANTLER2, and a NIMA-related kinase, AtNek6, regulate the epidermal cell morphogenesis in Arabidopsis.

Abstract

We isolate the tip growth mutant on the root hair cells, antlers1-1 (atl1-1), and identify the ATL1 gene by a positional cloning method. atl1-1 is an allele of the MZH2 kinesin-related gene, and we elucidate the structure of the ATL1 gene and a tissue-specific activity of its promoter. The ATL1 kinesin-related gene shows two homologus genes, named ATL2 and ATL3, in the Arabidopsis genome, and we report an involvement of the ATL2 gene in the helical growth of roots. Furthermore, by yeast two-hybrid screening, we isolate a NIMA-related protein kinase (Nek) gene, AtNek6, which encode a protein kinase bound to the C-terminus of the ATL family proteins. We reveal the function of AtNek6 in the epidermal cell morphogenesis in Arabidopsis seedlings. Our results shed light on the functions of the ARM repeat-containing kinesins and a NIMA-related kinase in epidermal cell morphogenesis of plants.