Microtubule defects and cell morphogenesis in the lefty1lefty2 tubulin mutant of Arabidopsis thaliana
Microtubule defects and cell morphogenesis in the lefty1lefty2 tubulin mutant of Arabidopsis thaliana
复制标题
DOI：
10.1093/pcp/pch026
复制
发表时间：
2004-02-01
影响因子：
4.9
通讯作者：
Hashimoto, T
中科院分区：
文献类型：
--
作者：
Abe, T;Thitamadee, S;Hashimoto, T
Lefty1和Lefty2分别是α-微管蛋白6和α-微管蛋白4上相同的显性-负性氨基酸替换所致，是拟南芥的半显性左手螺旋生长突变体。在这里，我们描述了受影响的微管蛋白基因的表达模式和左旋双突变体的表型，以解决微管缺陷对细胞形态发生的增加影响。这两种微管蛋白基因在所研究的组织和细胞类型中普遍表达，在拟南芥幼苗中，α-微管蛋白2/4/6亚家族转录本占主导地位。左侧双突变体幼苗在下胚轴中呈螺旋生长，在根伸长区细胞呈放射状扩张，突变体的皮层微管阵列比野生型微管阵列更加碎片化和排列不均匀。叶毛的分枝显著减少。在成年突变植株中，花药花丝细胞的各向异性生长严重受损。这些结果表明，当皮质微管越来越不稳定时，左手扭曲的伸长是导致完全各向同性扩张的中间状态。
lefty1 and lefty2 are semi-dominant left-handed helical growth mutants of Arabidopsis thaliana, which result from identical dominant-negative amino acid substitutions in alpha-tubulin 6 and a-tubulin 4, respectively. Here we characterized the expression patterns of the affected tubulin genes and the phenotypes of the lefty double mutant to address increasing effects of microtubule defects on cell morphogenesis. Both tubulin genes were expressed ubiquitously in examined tissue and cell types, and the a-tubulin 2/4/6 subfamily transcripts predominated over other a-tubulin transcripts in Arabidopsis seedlings. The lefty double mutant seedlings showed helical growth in hypocotyls and radial cell expansion in the root elongation zone where mutant cortical microtubule arrays were more fragmented and less well aligned than wild-type arrays. Branching of leaf trichomes was highly reduced. In adult mutant plants, anisotropic growth of anther filament cells was severely impaired. These results suggest that left-handed twisted elongation is an intermediate state that leads to full isotropic expansion as the cortical microtubules are increasingly destabilized.