New Gene Activates Regeneration in Flatworm Planarians to Regrow a Head

Scientists have discovered a new gene, called zic-1, that enables stem cells to regrow a head after decapitation in flatworm planarians. The new findings could allow researchers to learn a bit more about limb regeneration.

Many species across the animal kingdom have the ability to regenerate. Yet the mechanisms that connect injuries to stem cell activation and the production of new tissues are not fully understood. In the past, scientists have found that in the early embryo most animals use "tissue organizers" that secrete proteins to allow communication between cells for the formation of organs. But it hasn't been clear how these tissue organizers could potentially be produced from scratch in order to allow adult regeneration.

That's why scientists looked at planarians. In previous research, the scientists identified the secreted protein Notum as a component of a tissue organizer needed for head regeneration in planarians. Notum actually drives head regeneration by inhibiting Wnt signaling, which is a broadly used molecular pathway in cell communication.

In this case, the researchers found that expression of the Notum protein and head regeneration required the zic-1 gene, which encodes a DNA-binding protein activated in stem cells early after decapitation. This finding, in particular, helps researchers understand a bit more about regeneration in general.

The research has implications for humans and regenerative medicine. In theory, human stem cells could be used to build or repair complex tissues. By understanding the connection between Wnt signaling and zic-1 in the use of stem cells, researchers could possible use human stem cells in order to create tissue organizers for enhancement of injury repair. This, in particular, would be a huge boon in medicine and could help with severe injuries.

The findings are published in the journal PLOS Genetics.