Posted on 07/05/2009 1:16:57 PM PDT by neverdem
Tissues in axolotl amputees regenerate themselves by “memory”
Given a chance to regrow a limb, salamanders don’t change a thing.
Since the 18th century, scientists have puzzled over how salamanders regenerate amputated limbs and have looked for clues to regrow human limbs. Researchers thought they knew part of the answer: Cells at the wound site would lose their identities as they turned back their developmental clocks to become pluripotent stem cells — capable of developing into many cell types in the body — and then recreate the lost limb.
But a new study published July 2 in Nature and led by Elly Tanaka, a developmental biologist at the Center for Regenerative Therapies at the Dresden University of Technology in Germany, shows that cells left behind after amputation retain memories of their identities and proliferate to form the same type of tissue in the replacement limb.
“Definitely it’s putting the conventional wisdom upside-down,” says Alejandro Sánchez Alvarado, a Howard Hughes Medical Institute investigator at the University of Utah in Salt Lake City.
Tanaka and her colleagues genetically engineered a type of salamander called axolotls to make a green fluorescent protein in all cells of the body. This GFP allows the researchers to visually trace the fate of cells during regeneration. The researchers then transplanted muscle, skin, cartilage or nerve tissues from GFP-producing axolotls into embryos that do not make the glowing green protein. Animals that grew from the engineered embryos made GFP only in the transplanted tissues. The researchers then amputated one of the animal’s limbs and watched to see where GFP would appear in the regenerated appendage.
If cells were to become pluripotent before regenerating new limbs, the researchers would have expected to see GFP-producing cells sprinkled throughout the new limbs like salt and pepper, says Sánchez Alvarado.
But the...
(Excerpt) Read more at sciencenews.org ...
Nature News version & linked abstract
Fascinating. Thanks for the post.
regenerative medicine ping
“Axolotls”
I first came across these creatures by reading Mad Magazine about 50 years ago!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.