Laboratory of Molecular Biology and Cytometry, Department of Plant Genetics and Biotechnology, University of Technology and Life Sciences, Kaliskiego Ave. 7, 85-789 Bydgoszcz, Poland.
J Exp Bot. 2012 Jun;63(11):4165-78. doi: 10.1093/jxb/ers099. Epub 2012 Mar 26.
Early Arabidopsis thaliana seedling growth includes the highly synchronous development of hairs from every epidermal cell of the collet (the root-hypocotyl transition zone). The dynamics of collet hair growth, and accompanying nuclear movement and endoreduplication, were followed using a combination of different fluorescent probes for time-lapse imaging and flow cytometry. Using laser-scanning confocal microscopy on the double-transgenic Arabidopsis hybrid line NLS-GFP-GUS × YPM, there appeared to be a correlation between nuclear position and the cell tip during growth of the collet hair cells, as occurs in asynchronously developing root hairs. However, disruption of nuclear movement in the growing collet hairs using low concentrations of cytoskeletal inhibitors demonstrated that nuclear positioning close to the tip of the cell is not essential for tip-directed growth of the hair. Nuclear DNA content increases from 4C to 16C during development of the collet hairs. Following cessation of growth, nuclei moved to the base of the hairs and then their movement became asynchronous and limited. Co-visualization of RFP-highlighted prevacuolar vesicles and GFP-labelled nuclei showed that, whereas small vesicles allowed unimpeded nuclear movement within the hair, transient stops and directional reversals coincided with the presence of larger vesicles in close proximity to the nucleus. Arabidopsis collet hairs provide a robust, easily accessible, naturally synchronized population of single tip-growing cells that can be used as a model cell type for studying nuclear movement and endoreduplication.
早期拟南芥幼苗的生长包括从花托（根-下胚轴过渡区）的每个表皮细胞高度同步发育毛。使用不同的荧光探针组合进行延时成像和流式细胞术，跟踪花托毛生长以及伴随的核运动和内复制的动态。在双转基因拟南芥杂交系 NLS-GFP-GUS×YPM 上使用激光扫描共聚焦显微镜，在花托毛细胞生长过程中，核位置似乎与细胞尖端之间存在相关性，就像在异步发育的根毛中一样。然而，使用低浓度的细胞骨架抑制剂破坏生长中的花托毛中的核运动表明，核定位接近细胞尖端对于毛的尖端定向生长并不是必需的。核 DNA 含量在花托毛发育过程中从 4C 增加到 16C。生长停止后，核移动到毛的基部，然后它们的运动变得异步且受限。共可视化 RFP 标记的前液泡小泡和 GFP 标记的核显示，虽然小泡允许核在毛内无障碍运动，但短暂的停止和方向反转与靠近核的大泡的存在同时发生。拟南芥花托毛提供了一个强大的、易于接近的、自然同步的单一尖端生长细胞群体，可作为研究核运动和内复制的模型细胞类型。
