Peremyslov Valera V, Prokhnevsky Alexey I, Avisar Dror, Dolja Valerian V
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
Plant Physiol. 2008 Mar;146(3):1109-16. doi: 10.1104/pp.107.113654. Epub 2008 Jan 4.
Multigene families encoding class XI myosins are conserved in higher plants, however, little information is available on specific functions of these ubiquitous molecular motors. We isolated gene knockout mutants for all 13 class XI myosins present in Arabidopsis (Arabidopsis thaliana) genome. Inactivation of 11 myosin genes resulted in no discernible phenotypes under the normal growth conditions. In contrast, the knockouts of the remaining two myosin genes, XI-2 (formerly MYA2) and XI-K, exhibited similar defects in root hair elongation suggesting that the myosin-driven motility plays a significant role in a polar tip growth. Strikingly, inactivation of each of these myosins also reduced trafficking of Golgi stacks, peroxisomes, and mitochondria in root hairs and in leaf epidermal cells. These results indicate that myosins XI-K and XI-2 play major and overlapping roles in the cell dynamics in Arabidopsis and highlight the redundant nature of myosin function in plants.
编码XI类肌球蛋白的多基因家族在高等植物中是保守的，然而，关于这些普遍存在的分子马达的具体功能，目前可用信息很少。我们分离了拟南芥基因组中存在的所有13种XI类肌球蛋白的基因敲除突变体。11个肌球蛋白基因的失活在正常生长条件下未导致明显的表型。相比之下，其余两个肌球蛋白基因XI-2（以前称为MYA2）和XI-K的敲除在根毛伸长方面表现出相似的缺陷，这表明肌球蛋白驱动的运动在极性顶端生长中起重要作用。引人注目的是，这些肌球蛋白中的每一个的失活也减少了根毛和叶表皮细胞中高尔基体堆叠、过氧化物酶体和线粒体的运输。这些结果表明，肌球蛋白XI-K和XI-2在拟南芥的细胞动态中发挥主要且重叠的作用，并突出了植物中肌球蛋白功能的冗余性质。
