Development and regeneration

Biological program triggered by large injuries not required for regeneration, Whitehead Institute team finds

By investigating regeneration in planarian flatworms, Whitehead Institute researchers have identified a mechanism—involving the interplay of two wound-induced genes—by which the animal can distinguish between wounds that require regeneration and those that do not.

By studying the planarian flatworm, a master of regenerating missing tissue and repairing wounds, the lab of Whitehead Institute Member Peter Reddien has identified an unexpected source of position instruction: the muscle cells in the planarian body wall. This is the first time that such a positional control system has been identified in adult regenerative animals.

Whitehead Institute researchers have created a complete catalog of genes active in the planarian eye. Several identified genes are known to have versions that play a role in the vertebrate eye, including genes involved in eye development and others associated with age-related macular degeneration and Usher syndrome, a disorder that causes progressive retinal degradation.

Despite their unassuming appearance, the planarian flatworms in Whitehead Institute Member Peter Reddien's lab are revealing powerful new insights into the biology of stem cells—insights that may eventually help such cells deliver on a promising role in regenerative medicine.

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.