Sea urchin embryonic cilia.

Cilia are exceptionally complicated subcellular structures involved in swimming and developmental signaling, including induction of left-right asymmetry in larval stages. We summarize the history of research on sea urchin embryonic cilia. The high salt method to isolate cilia is presented first; methods to block cilia formation and to lengthen cilia are presented in the appendix. Evidence suggests that regenerated cilia may not be as physiologically perfect as those formed normally during embryogenesis. Sea urchin embryonic cilia are valuable models for studying molecular details of cilia assembly and differentiation as well as gene activation, cell signaling, and pattern formation during development.