Scientists Discover the Key to Axolotls’ Ability to Regenerate Limbs (wired.com)
“Our big surprise was to discover that the key was not in how much retinoic acid was produced, but in how it was degraded,” says Monaghan. The team discovered that cells in the distal part of the limb, the wrist, are awash in an enzyme called CYP26B1, whose sole function is to destroy retinoic acid. In contrast, cells in the shoulder have hardly any of this enzyme, allowing retinoic acid to accumulate to high levels.
This difference creates a chemical gradient along the limb: lots of retinoic acid in the shoulder, little in the wrist. It is this gradient that informs cells of their exact location.
This is fascinating on several levels. First, just the idea that there is a possibility that humans have an ability to regenerate limbs is amazing. Second, this reminds me that chemical gradients, which are mathematics at their core, play an important role in so many aspects of biology and medicine. And lastly, this really shows the possibilities unlocked by public funding of basic research. Kudos to Wired for reporting this, in a thorough manner, to a broader audience.
Here’s the original Nature paper.