Break of symmetry in regenerating tobacco protoplasts is independent of nuclear positioning

• Published in: Journal of integrative plant biology 2016-09, Vol.58 (9), p.799-812
• Main Authors: Brochhausen, Linda, Maisch, Jan, Nick, Peter
• Format: Article
• Language: English
• Subjects: Actins - metabolism; Axis formation; Body Patterning; Cell Nucleus - metabolism; Cell Polarity; Cell Proliferation; Chromatin - metabolism; cytoskeleton; Green Fluorescent Proteins - metabolism; Histones - metabolism; Kinesins - metabolism; Models, Biological; Nicotiana - physiology; nuclear migration; Plant Proteins - metabolism; polarity induction; Protoplasts - cytology; Protoplasts - metabolism; Protoplasts - physiology; Regeneration; Time-Lapse Imaging; tobacco BY-2 protoplast; 再生; 同源结构域; 对称性; 染色质结构; 核定位; 植物细胞; 烟草原生质体; 细胞骨架
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12469

Nuclear migration and positioning are crucial for the morphogenesis of plant cells. We addressed the potential role of nuclear positioning for polarity induction using an experimental system based on regenerating protoplasts, where the induction of a cell axis de novo can be followed by quantification of specific regeneration stages. Using overexpression of fluorescently tagged extranuclear （perinu- clear actin basket, kinesins with a calponin homology domain （KCH）） as well as intranuclear （histone H2B） factors of nuclear positioning and time-lapse series of the early stages of regeneration, we found that nuclear position is no prerequi- site for polarity formation. However, polarity formation and nuclear migration were both modulated in the transgenic lines, indicating that both phenomena depend on factors affecting cytoskeletal tensegrity and chromatin structure. We integrated these findings into a model where retrograde signals are required for polarity induction. These signals travel via the cytoskeleton from the nucleus toward targets at the plasma membrane.