If a zebrafish loses a chunk of its tail fin, it'll grow back within a week. Like lizards, newts, and frogs, a zebrafish can replace surprisingly complex body parts. A tail fin, for example, has many different types of cells and is a very intricate structure. It is the fish version of an arm or leg.
The question of how cold-blooded animals re-grow missing tails and other appendages has fascinated veterinary and medical scientists. They also wonder if people, and other warm-blooded animals that evolved from these simpler creatures, might still have untapped regenerative powers hidden in their genes.
People are constantly renewing blood components, skeletal muscles and skin. We can regenerate liver tissue and repair minor injuries to bone, muscle, the tips of our toes and fingers, and the corneas of our eyes. Finding out more about the remarkable ability of amphibians and fish to re-grow complex parts might provide the information necessary to create treatments for people whose hearts, spinal cords, eyes or arms and legs have been badly hurt.
Scientists have discovered some of the genes and cell-to-cell communication pathways that enable zebrafish to restore their tail fins.
"The ability to regenerate body parts such as those that are damaged by injury or disease," said Dr. Randall Moon, professor of pharmacology at the University of Washington (UW), an investigator of the Howard Hughes Medical Institute, and a researcher in the UW Institute for Stem Cell and Regenerative Medicine, "involves creating cells that can take any number of new roles. This can be done by re-programming cells that already have a given function or by activating resident stem cells."
Developmental biologists know that a particular kind of cell-to-cell communication, called Wnt/Beta-catenin signaling, regulates the fate of these as-yet undeveloped cells as an embryo forms. Through a cascade of signals, cells waiting for their calling learn which
Contact: Leila Gray
University of Washington