Cytoskeleton and nucleoskeleton involvement in processes of cytomixis in plants.

Abstract

Cytomixis is a form of cell-to-cell nuclear migration that involves the interaction of dynamic cytoskeletal components with the nucleus through signalling systems and linker complexes. In cytomixis two known mechanisms can be involved: actomyosin and/or microtubules and their associated motors. Perinuclear actin anchors and determines the direction of nuclear movement. In microsporogenesis cytomixis is probably initiated by a cascade of signals that trigger prophase reorganization of nucleus and cytoskeleton, and is a result of cytoskeletal protein activation, as well as a weakening of mechanisms responsible for anchoring the nucleus. The interactions between nuclei and the cytoskeleton are mediated by linker complexes that play a major role in nuclear positioning and shape, chromatin-nuclear envelope interactions, nucleoskeleton organization, gene expression and genome organization. Other contributing factors include changes in the protein composition and post-translational modifications that alter protein conformation. Cytomixis appears also to have relevance to higher order structuring, influencing tissue and organ architecture, causing collective forms of cell interactions and information exchange within a single continuum. In this review we summarize our current understanding of the cytoskeleton dynamic function in cytomictic nuclear migration.