The properties and regulations of proteins to form cytoskeletons in higher plants

我们研究了高等植物细胞骨架元素及其蛋白质组成的性质和功能。培养的烟草细胞含有少量的微管蛋白，免疫学分类为-lt；α-微管蛋白。这种蛋白诱导微管解聚，抑制微管聚合。用微管蛋白抗体进行的免疫荧光研究经常显示，微管从细胞核表面伸向细胞质，有时伸到细胞核内，就像纺锤体微管的形成一样。这一观察表明，类MTOC物质在细胞核上有分布。实际上，类MTOC活性物质(S)是从高等植物的细胞核中制备出来的。体外可聚合的肌动蛋白是从高等植物细胞中分离出来的。其生化性质很快就会显示出来。我们在高等植物细胞中发现了三个新的细胞骨架元件。它们似乎是高等植物特有的细胞骨架，因此，…是从高等植物的细胞核中分离出来的50kd的蛋白在鸟苷核苷酸存在下聚合成中间丝状结构。该蛋白被证明是碱性蛋白，并与抗微管蛋白抗体发生交叉反应。单抗显示50kd的蛋白定位于细胞核周围，皮质区呈网状分布在间期细胞中。这种蛋白质很容易被ATP耗尽而溶解，ATP的加入诱导了可逆聚合，并形成了直径约3[5 nm]的细丝纤维束，单抗显示这种纤维束分布在突出到质膜的细胞核表面。纤丝束可能参与了决定胞质分裂发生的部位以及细胞核相对于分裂部位的移动的机制。100kd的蛋白质用不溶部分的Kc1溶解并纯化。该蛋白质在体外聚合了直径约15 nm的双链细丝。这些细胞骨架元件的功能有待进一步研究。较少

We have studied about the properties and functions of cytoskeletal elements and its protein compositions in higher plants.Cultured tobacco cells possess minor tubulin-like protein,which is immunologically classified as <alpha>-tubulin. This protein induced the depolymerization and the inhibition of polymerization of microtubules.Immunofluorescent studies using antibodies against tubulin often showed the microtubules protruding from the surface of nuclei to cytoplasm and sometimes to inside of nuclei just like the initiation of spindle microtubules formation.This observation suggested the localization of MTOC-like substances on nuclei.In fact,MTOC-like active substance(s)was prepared from nuclei of higher plants.In vitro polymerizable actin was isolated from hifer plant cells.The biochemical properties would be shown within short time.We found three novel cytoskeletal elements from higher plant cells.They seems to be unique cytoskeletons in higher plants,therefore,the regulation systems … More will be interest.50 kd protein polymerizad intermediate filament-like structures in the presence of guanosine nucleotides.This protein was shown to be basic protein and cross-reacted with antitubulin antibodies.Monoclonal antibodies showed the localization of 50 kd protein around the nuclei and cortical region as network in interphase cells.Phragmoplast was also shown to contain this protein.58 kd protein was purified from insoluble fraction in the presence of ATP,this protein readily solubilized by the depletion of ATP.Addition of ATP induced the reversible polymerization and formed fibrillar bundles of thin filament having a diameter about 3[5 nm.Monoclonal antibodies showed the distribution of this bundles around the surface of nuclei protruding to plasma membrane. Possible involvement of the fibrillar bundles in the mechanism to determine the site at which cytokinesis will occur and to move the nucleus in relation to the division site.100 kd protein was solubilized with KC1 fron insoluble fraction and purified.This protein polymerized double chain filaments haying a diameter about 15 nm in vitro.The function of these cytoskeletal element should be further studied. Less