Department of Sciences of Seed Industry, College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, The People's Republic of China.
Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing, The People's Republic of China.
Planta. 2017 Oct;246(4):687-700. doi: 10.1007/s00425-017-2723-7. Epub 2017 Jun 24.
GhVLN4 exhibited activity of cross-linking actin filaments into bundles. Overexpression of GhVLN4 increased the abundance of thick actin bundles and resulted in longer cell phenotypes. Actin bundle is a dynamic, higher-order cytoskeleton structure that is essential for cell expansion. Villin is one of the major proteins responsible for crosslinking actin filaments into bundles. However, this kind of actin binding protein has rarely been investigated in cotton. In the present work, a cotton villin gene was molecularly cloned from Upland cotton and denominated as GhVLN4. This gene was more highly expressed in fiber-bearing wild-type cotton TM-1 (Texas Marker-1) than in Ligon lintless-1 mutant (Li-1). Biochemical analysis combined with subcellular localization revealed that GhVLN4 is an actin-binding protein performing actin filament bundling activity in vitro. In line with these findings, a greater abundance of thick actin filament bundles were observed in GhVLN4-overexpressing transgenic plants compared with those in wild-type control. Moreover, ectopic expression of GhVLN4 significantly enhanced the cell length-width ratio of Schizosaccharomyces pombe yeast and increased the length of various Arabidopsis cells, including root cells, root hairs and pollen tubes. Taken together, our results demonstrate that GhVLN4 is involved in the generation of actin filament bundles, suggesting that GhVLN4 may play important roles in regulating plant cell morphogenesis and expansion by remodeling actin cytoskeleton.
GhVLN4 表现出将肌动蛋白丝交联成束的活性。GhVLN4 的过表达增加了厚肌动蛋白束的丰度，并导致细胞表型变长。肌动蛋白束是一种动态的、高级的细胞骨架结构，对细胞扩张至关重要。Villin 是将肌动蛋白丝交联成束的主要蛋白质之一。然而，这种肌动蛋白结合蛋白在棉花中很少被研究。在本工作中，从陆地棉中克隆了一个棉花 villin 基因，并命名为 GhVLN4。该基因在纤维携带的野生型棉花 TM-1（德克萨斯标记-1）中比 Ligon lintless-1 突变体（Li-1）表达更高。生化分析结合亚细胞定位表明，GhVLN4 是一种肌动蛋白结合蛋白，具有体外肌动蛋白丝成束活性。与这些发现一致的是，在 GhVLN4 过表达的转基因植物中观察到更多的厚肌动蛋白丝束的丰度增加与野生型对照相比。此外，GhVLN4 的异位表达显著提高了酿酒酵母 Schizosaccharomyces pombe 的细胞长宽比，并增加了各种拟南芥细胞的长度，包括根细胞、根毛和花粉管。总之，我们的结果表明，GhVLN4 参与肌动蛋白丝束的生成，表明 GhVLN4 可能通过重塑肌动蛋白细胞骨架在调节植物细胞形态发生和扩张中发挥重要作用。
