Abstract
End-Binding 1 (EB1) is a plus end-tracking protein family highly conserved in eukaryotes. Arabidopsis thaliana has three EB1 proteins (AtEB1a, AtEB1b, and AtEB1c) although functional divergence among Arabidopsis EB1 members are unclear. We previously demonstrated that AtEB1c is expressed in meristematic cells and the protein contains a nuclear localization signal in its unique C-terminal tail region. We here show that ateb1c mutant seedlings were hypersensitive to oryzalin.
In the ateb1c cells, spindle and phragmoplast microtubules did not align precisely with respect to the cell division axis. Complementation tests indicated that the unique C-terminal tail of AtEB1c was necessary for rescue of this ateb1c defect. When tobacco EB1c was suppressed in cultured cells by RNAi, lagging chromosomes were observed at high frequencies. Moreover, AtEB1c-GFP colocalized with an RFP-CenH3 kinetochore marker. These results suggest that AtEB1c specifically functions in regulating mitotic MTs.
