Frank Johnson and Osamu Shimomura discovered a jellyfish protein that glows green when exposed to UV light in 1961. Similar proteins are also used to fluoresce corals in a variety of colors. According to a paper in Developmental Cell, Harvard University scientists have genetically modified the three banded pantherworm to produce a similar green glow. They hope to discover the secrets of regeneration.
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Regeneration is a common trait in animals. Some creatures can do extraordinary regenerative feats. This could have implications for human aging. For example, a salamander can grow a leg if it loses one. Some geckos can disarm their tails to distract predators, and then regrow them later. A zebra fish can repair a broken heart, retina, brain, pancreas, spine, or other damage. A jellyfish, a planarian flatworm or a sea anemone can be cut in half to regenerate their entire bodies.
The three-banded pantherworm (Hofstenia Miamia) is another tiny creature. It looks almost like a grain of rice and has three cream-colored stripes running across its body. Each panther worm can be cut into three pieces and will form a fully formed worm in eight weeks. These worms can be found in Japan, the Bahamas, Bermuda and the Caribbean. These worms also provide a promising model to study the mechanics and regeneration.
Coauthor Mansi Srivastava is an evolutionary biologist from Harvard University. She has been studying the three banded panther worm ever since 2010 when she was a postdoc student in Peter Reddien’s lab at MIT’s Whitehead Institute. The worms were collected in Bermuda by the team and brought back to Cambridge. They did not adapt immediately to laboratory life. Reddien and Srivastava had to determine the right salinity levels for their water, and find a suitable food source. Reddien's planarian flatworms were fed to the worms and they didn't like it. Some worms turned to cannibalism for survival. The researchers eventually discovered that panther worms love brine shrimp, also known as sea monkeys. This allowed them to flourish and begin to breed.
1960's report claimed that the worms could regrow their heads. However, there was not much scientific evidence. Reddien's and Srivastava’s initial experiments showed that panther worms can not only regrow their heads but they can also regenerate any body part just like planarian flatworms, even though the two are not closely related. Srivastava runs her own lab at Harvard to study regeneration in pantherworms.
Srivastava's lab published the complete genome sequence of the pantherworm in 2019, as well as the identification of several "DNA switches" that control genes for whole-body regeneration. They identified a portion of noncoding DNA that controls the activation of a master control gene for regeneration, called early growth response (EGR). EGR can turn on other genes involved in different processes. Regeneration in the worms is impossible if EGR isn’t activated.
