植物微管结合蛋白AtMAP65-1在拟南芥气孔保卫细胞中的定位(简报)

植物细胞微管骨架的不同排列方式对细胞的生长分化及形态建成具有重要意义,微管的这种动态组织行为不仅需要自身的组成蛋白-微管蛋白(tubulin),还要有微管辅助蛋白MAPs(Microtubule-associated proteins)的参与[1,2]。即MAPs是一类能够与微管骨架特异结合并调节其动态装配过程及其结构、进而影响微管功能的蛋白大分子。其中,MAP65是最先在烟草悬浮细胞BY-2中纯化出来的、分子量约为65KDa的一个微管结合蛋白家族。

LOCALIZATION OF MICROTUBULE-ASSOCIATED PROTEIN AtMAP65-1 IN GUARD CELLS OF ARABIDOPSIS

AtMAP65-1 gene was cloned from Arabidopsis genome. A plant expression vector containing AtMAP65-1-GFP fusion gene driven by 35S promoter was constructed and introduced into Arabidopsis by Agrobacterium infection. Under confocal laser scanning microscope (CLSM), it was found that in the light-induced opening guard cells AtMAP65-1 was distributed radiately from dorsal wall to ventral wall in a bundling way. Treated with microtubule specific inhibitor-Vinblastine (10 micromol/L) for 90 min, the organization of AtMAP65-1 in guard cell was disrupted dramatically. Following the depolymerization of cortical microtubule and the decreasing of stomatal aperture, the fluorescence of AtMAP65-1 became to be fragmented into dotted spots. The organization of AtMAP65-1 was broken up completely when the treatment was up to 120 min. In the dark-induced closing guard cells, AtMAP65-1 was turned into fragments and was randomly dispersed throughout the cells. That is, AtMAP65-1 is co-localized with cortical microtubules. The results suggest that AtMAP65-1 binds cortical microtubules, and it may regulate the arrangement of cortical microtubules, which helps us gain more insights into the role of AtMAP65-1 in stomatal movement.