Kirik Victor, Grini Paul E, Mathur Jaideep, Klinkhammer Irene, Adler Klaus, Bechtold Nicole, Herzog Michel, Bonneville Jean-Marc, Hülskamp Martin
Botanical Institute III, University of Köln, Gyrhofstrasse 15, 50931 Köln, Germany.
Plant Cell. 2002 Sep;14(9):2265-76. doi: 10.1105/tpc.003020.
The control of the stoichiometric balance of alpha- and beta-tubulin is important during microtubule biogenesis. This process involves several tubulin-folding cofactors (TFCs), of which only TFC A is not essential in mammalian in vitro systems or in vivo in yeast. Here, we show that the TFC A gene is important in vivo in plants. The Arabidopsis gene KIESEL (KIS) shows sequence similarity to the TFC A gene. Expression of the mouse TFC A gene under the control of the 35S promoter rescues the kis mutation, indicating that KIS is the Arabidopsis ortholog of TFC A. kis plants exhibit a range of defects similar to the phenotypes associated with impaired microtubule function: plants are reduced in size and show meiotic defects, cell division is impaired, and trichomes are bulged and less branched. Microtubule density was indistinguishable from that of the wild type, but microtubule organization was affected in trichomes and hypocotyl cells of dark-grown kis plants. The kis phenotype was rescued by overexpression of an alpha-tubulin, indicating that KIS is involved in the control of the correct balance of alpha- and beta-tubulin monomers.
在微管生物发生过程中，α-微管蛋白和β-微管蛋白化学计量平衡的控制至关重要。这一过程涉及多种微管蛋白折叠辅助因子（TFCs），其中只有TFC A在哺乳动物体外系统或酵母体内并非必需。在此，我们表明TFC A基因在植物体内很重要。拟南芥基因KIESEL（KIS）与TFC A基因具有序列相似性。在35S启动子控制下的小鼠TFC A基因表达可挽救kis突变，表明KIS是TFC A在拟南芥中的直系同源基因。kis植物表现出一系列类似于与微管功能受损相关的表型缺陷：植株变小，出现减数分裂缺陷，细胞分裂受损，毛状体凸起且分支减少。微管密度与野生型无差异，但在黑暗生长的kis植物的毛状体和下胚轴细胞中微管组织受到影响。通过过表达α-微管蛋白可挽救kis表型，表明KIS参与α-和β-微管蛋白单体正确平衡的控制。
