Newts’ limbs re-grow via protein; discovery could help humans

Scientists have found a key protein that helps newts re-grow severed limbs, a discovery that may guide future research into human regenerative medicine.

Biologists have long been intrigued and perplexed by the ability of newts and salamanders to regenerate damaged body parts.

A British team’s research, published Friday in the journal Science, shows that a protein called nAG, secreted by nerve and skin cells, plays a central role in producing a clump of immature cells called a blastema, which regenerates the missing part.

Even when a nerve was severed below the stump tip, which would normally prevent regrowth, the scientists were able to coax regeneration by artificially making cells produce the protein -- demonstrating the importance of nAG.

A clear understanding of the molecular signals involved in blastema formation and limb regeneration could eventually allow doctors to program similar patterns into cells of nonregenerating body parts.

In effect, newts are able to manipulate their bodies by turning cells into undifferentiated stem cells and then back into mature tissue.

It is a clever trick -- but understanding how they do it does not mean humans will necessarily be able to copy them and regenerate lost arms or legs, according to one of the researchers, Jeremy Brockes, a professor at University College London.

“It would be very desirable for regenerative medicine to understand the specification of the blastema and to try to re-create that in a mammalian context,” he said. “But we are a long way away from being able to do that.”