McClinton R S, Sung Z R
Department of Plant Biology, University of California, Berkeley 94720-3102, USA.
Planta. 1997;201(3):252-60. doi: 10.1007/s004250050064.
To understand the role of microtubules in the regulation of cell elongation, we characterized microtubule patterns in fass, a cell shape mutant of Arabidopsis thaliana (L.) Heynh. Examining microtubule patterns via immunocytochemistry, we found that fass cells were able to organize their microtubules into mitotic spindles and phragmoplasts. During interphase or preprophase, fass cells had cortical microtubules, verified by transmission electron microscopy, but these microtubules were not organized into the cortical array or preprophase band. Using chromatin condensation and tubulin localization on the nuclear envelope as preprophase stage markers, we found that although fass cells lacked the preprophase band and cortical array, their cell division cycle appeared normal. To pinpoint the defect in fass cells, we delineated the sequential events leading to cortical array formation in Arabidopsis cells and found that fass cells initiated and recolonized cortical microtubules in the same manner as wild-type cells, but failed to order them into the cortical array. Taken together, these results suggest fass cells are impaired in a component of the microtubule organizing center(s) required for the proper ordering of cortical microtubules at the plasma membrane.
为了解微管在细胞伸长调节中的作用，我们对拟南芥（L.）海因的细胞形状突变体fass中的微管模式进行了表征。通过免疫细胞化学检查微管模式，我们发现fass细胞能够将其微管组织成有丝分裂纺锤体和成膜体。在间期或前期，fass细胞具有皮层微管，这通过透射电子显微镜得到证实，但这些微管没有组织成皮层阵列或前期带。利用染色质凝聚和核膜上微管蛋白定位作为前期阶段标记，我们发现尽管fass细胞缺乏前期带和皮层阵列，但其细胞分裂周期似乎正常。为了确定fass细胞中的缺陷，我们描绘了拟南芥细胞中导致皮层阵列形成的连续事件，发现fass细胞以与野生型细胞相同的方式起始并重新定殖皮层微管，但未能将它们排列成皮层阵列。综上所述，这些结果表明fass细胞在质膜上皮层微管正确排列所需的微管组织中心的一个组分中存在缺陷。
