Stem Cells

Whitehead Institute researchers have determined that the planarian flatworm regenerates missing tissues by using pluripotent adult stem cells. Until now, scientists could not determine whether the dividing cells in planarians, called neoblasts, are a mixture of specialized stem cells that each regenerates specific tissues, or if individual neoblasts are pluripotent and able to regenerate all tissues.

A little-studied gene known as notum plays a key role in the planarian’s regeneration decision-making process, according to Whitehead Institute scientists. At head-facing (anterior) wounds, the gene notum acts as a dimmer switch to dampen the Wnt pathway—an ancient signaling circuit that operates in all animals—and promote head regeneration.