Retinoic acid plays a key role in proximodistal positional identity in axolotl limb regeneration
If your toe got chopped off, you wouldn’t want a whole foot to grow back in its place. Neither would an axolotl, whose remarkable limb regeneration powers make this a more real possibility. Regenerating limbs retain their ‘proximodistal identity’ (ie. how far away they are from the body) thanks to genes that guide cells in the growing stump. Retinoic acid is known to regulate these genes, but how its levels are managed is unclear. Researchers hoping that axolotl biology could hold clues to improving human tissue repair discovered that the rate of retinoic acid breakdown is key. Reducing this breakdown led to structural errors, like regenerating the wrong limb segments (middle row), while fully blocking it caused regeneration to fail altogether (bottom). Understanding how positional identity is established is fundamental to tissue engineering and could even let us help the body repair and regrow without putting a foot wrong.
Written by
BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.