The Role Of Two Microtubule-associated Proteins In Cell Morphogenesis

In this study,we used AtMAP65-1、AtMAP65-2 overexpression Arabidopsis thaliana,and AtMAP65-1 mutant to examine the shapes of pavement cells and the microtubule dynamic behaviors with Confocal-laser-scanning microscope.The results were as follows:(ⅰ) Confocal-Laser-scanning microscopy analysis of the cellular phenotype showed that the leaf pavement cells of the wild-type were typical in having pronounced lobes resulting in a jigsaw puzzle-like appearance,whereas pavement cells of the over expressing AtMAP65-1 showed either no lobes or lobes that were much less pronounced.The semi-quantitatively RT-PCR results showed that the extent of morphological changes increased with the degree of MAP65-1 expression.(ⅱ) In addition to the loss of pavement cell lobes,cortical microtubules became more orderly when MAP65-1 was over expressed,compared to the random network of MTs in control.(ⅲ) MAP65-1 mutant led to little malformation of the pavement cells, however,the shape of root hair was significantly altered in mutants.(ⅳ) over expression of MAP65-2 also caused the irregular configuration of pavement cells, similar with over expression of MAP65-1.Furthermore,most of the MAP65-2 exhibited diffusely and freely throughout the cortex,but sometimes they bound to the microtubules in clear arrays.Our data indicate that both MAP65-1 and MAP65-2 involve in cell morphology,MAP65-1 may play an important role in regulating directional cell growth and cortical microtubule organization by stabilizing microtubules.