(A) A schematic representation of the CAE1/MRH2 genomic structure and domain organization. Upper panel, the CAE1/MRH2 genomic structure. Solid boxes indicate exons and solid lines indicate introns. The cae1-1 mutation site and the T-DNA insertion sites for mrh2-1 and mrh2-2 were indicated. cae1-1 was renamed to mrh2-3. Lower panel, domain feature of the 1051 amino acid-containing MRH2 protein. Numbers above indicate the positions of amino acids. Motor domain, the catalytic domain of kinesin motor (102–449); CC, coiled-coil (452–765); ARM, the ARM repeat domain (792–915). (B) RT-PCR analysis of MRH2 expression in cae1-1 CA1-1. ACT2, the internal control. (C) cae1-1 failed to complement mrh2-1 and mrh2-2, respectively. Root hairs of F1 for both crosses (cae1-1×mrh2-1, and cae1-1×mrh2-2) were shown, together with their parents.