Preprint Highlight: Building the cytokinetic contractile ring in an early embryo: initiation as clusters of myosin II, anillin and septin, and visualization of a septin filament network.

Abstract

Cytokinesis is driven by a contractile ring whose key components are well defined, yet how they are organized and how the contractile ring assembles and constricts remain unclear. This study combines confocal and superresolution imaging of endogenous contractile ring components in sea urchin embryos (in vivo) and isolated embryo cortices (ex vivo) to demonstrate that anillin and septin2 assemble into myosin II-positive clusters. The author surmises that these clusters are precursors to the contractile ring and observe septin filament nanostructure for the first time in an animal cell contractile ring. These insights into the organization of lesser studied yet conserved contractile ring proteins, anillin and septins, provide clues to their function and pave the way for similar studies in other animal species.