Valster A. H., Pierson E. S., Valenta R., Hepler P. K., Emons AMC.
Department of BioMolecular Sciences, Wageningen Agricultural University, Arboretumlaan 4, NL-6703 BD Wageningen, The Netherlands.
Plant Cell. 1997 Oct;9(10):1815-1824. doi: 10.1105/tpc.9.10.1815.
We have examined the cytological effects of microinjecting recombinant birch profilin in dividing and interphase stamen hair cells of Tradescantia virginiana. Microinjection of profilin at anaphase and telophase led to a marked effect on cytokinesis; cell plate formation was often delayed, blocked, or completely inhibited. In addition, the initial appearance of the cell plate was wrinkled, thin, and sometimes fragmented. Injection of profilin at interphase caused a thinning or the collapse of cytoplasmic strands and a retardation or inhibition of cytoplasmic streaming in a dose-dependent manner. Confocal laser scanning microscopy of rhodamine-phalloidin staining in vivo revealed that high levels of microinjected profilin induced a degradation of the actin cytoskeleton in the phragmoplast, the perinuclear zone, and the cytoplasmic strands. However, some cortical actin filaments remained intact. The data demonstrate that profilin has the ability to act as a regulator of actin-dependent events and that centrally located actin filaments are more sensitive to microinjected profilin than are cortical actin filaments. These results add new evidence supporting the hypothesis that actin filaments play a crucial role in the formation of the cell plate and provide mechanical support for the cytoplasmic strands in interphase cells.
我们研究了向弗吉尼亚紫露草正在分裂和处于间期的雄蕊毛细胞显微注射重组桦树肌动蛋白单体结合蛋白（profilin）的细胞学效应。在后期和末期显微注射肌动蛋白单体结合蛋白对胞质分裂产生显著影响；细胞板形成常常延迟、受阻或完全被抑制。此外，细胞板最初出现时呈皱缩、变薄，有时还会断裂。在间期注射肌动蛋白单体结合蛋白会导致细胞质丝变薄或塌陷，并以剂量依赖的方式使细胞质流动减缓或受到抑制。体内罗丹明 - 鬼笔环肽染色的共聚焦激光扫描显微镜观察显示，高剂量显微注射的肌动蛋白单体结合蛋白会导致成膜体、核周区域和细胞质丝中的肌动蛋白细胞骨架降解。然而，一些皮层肌动蛋白丝仍保持完整。数据表明，肌动蛋白单体结合蛋白有能力作为肌动蛋白依赖性事件的调节因子，并且位于细胞中央的肌动蛋白丝比皮层肌动蛋白丝对显微注射的肌动蛋白单体结合蛋白更敏感。这些结果为肌动蛋白丝在细胞板形成中起关键作用这一假说增添了新证据，并为间期细胞中的细胞质丝提供了机械支撑。
