蛋白酶体活性缺失对拟南芥根发育影响的显微和超微结构观察

以拟南芥根为材料,运用光学和透射电子显微镜分析了蛋白酶体抑制剂MG132对拟南芥根尖伸长区细胞的显微及超微结构的影响。结果发现:(1)微分干涉显微镜观察结果表明,MG132处理将导致拟南芥根部伸长区细胞的细胞质液泡化,并且抑制剂浓度越高细胞质液泡化越明显。(2)半薄切片结合考马斯亮蓝染色结果表明,MG132诱导的液泡中富含蛋白质。(3)免疫荧光标记结合共聚焦显微镜观察结果表明,液泡中的蛋白质主要为泛素缀合蛋白,暗示泛素化蛋白质的积累诱导细胞质自体吞噬的发生。(4)透射电镜观察结果表明,MG132处理的确诱导了自体吞噬作用的发生以及随后发生的自噬起源的细胞质液泡化。该研究结果为泛素/蛋白酶体途径与自体吞噬依赖的蛋白降解系统之间的联系提供了线索。

Microstructure and Ultrastructure Observasion of Primary Root Development in Arabidopsis thaliana with Proteasome Malfunction

Microstructure and ultrastructure observasion of primary root development in Arabidopsis thaliana with MG132 treatment were carried out using optical and electron microscope.(1)The differential interference contrast (DIC) observation indicated that MG132 induced cytosolic vacuolization in root cells in a dose-dependent manner.(2)Coomassie Brilliant Blue staining indicated that MG132-induced vacuoles were filled with proteins.(3)Immunofluorescence labeling with anti-ubiquitin antibody reveled the accumulation of the ubiquitinated proteins in vacuoles,suggesting a promotion of autophagic vacuolization in response to proteasome malfunction.(4)TEM observation confirmed the formation of autolysosomes in root cells.In summary,our result revealed the promotion of autophagy-derived vacuolization in response to proteasome malfunction,thus provide a new evidences of the functional link between the ubiquitin/proteasome pathway and autophagic vacuolization.