Tuesday , November 24 2020

Newly discovered DNA switches could allow people to count limbs



This picture taken on January 16, 2019 shows jellyfish in a tank during the opening of the new Aquarium of the Aquarium of Paris.

Philippe Lopez / AFP

People can one day have the ability to regain limbs after Harvard University researchers uncovered the DNA switch that controls whole-body genes generation.

Some animals get extraordinary repairs. Salamanders regrow legs, and geckos can throw their tails to escape predators and form new ones in two months. Planar worms, jellyfish and sea anemones can regenerate the entire body after being cut in half.

Now, researchers have found that a portion of non-coding or "junk" DNA controls the activation of a "master control gene" called early growth response (EGR) in three-band panther worms. It acts as a switch and enables or disables regeneration.

"We could reduce the activity of this gene and we found that if you don't have EGR, nothing happens," says Srivastava, assistant professor of organisms and evolutionary biology at Harvard. "The animals just can't regenerate. All the downstream genes won't turn on, so the other contacts don't work and the whole house goes dark, basically."

Importantly, humans also carry EGR and produce it when the cells are stressed and in need of repair. Nevertheless, it does not seem to trigger large-scale regeneration.

Scientists believe that the master gene is linked differently in humans and is trying to find a way to adapt its circuit to harvest its regenerative benefits.

The animals just can't regenerate. All the downstream genes will not turn on, so the other contacts do not work and the whole house goes dark, basically

Postdoctoral candidate Andrew Gehrke from Harvard believes the answer lies in the area of ​​non-coding DNA that controls the gene. This DNA was once supposed to do something, but in recent years, researchers have realized that it has a great influence.

"Only about two percent of the genome does things like proteins," says Gehrke. "We wanted to know: What are the other 98 percent doing in whole body regeneration?

"I think we've just scratched the surface. We've looked at some of these switches, but there's a completely different aspect of how the genome interacts on a larger scale, and all that's important to turning on and off genes."

Srivastava added: "The question is: If humans can turn on EGR and not just turn it on, but do it when our cells are damaged, why can't we regenerate?

"It's a very natural question to think if a gecko can do this, why can't I? The answer might be that if the EGR is the power switch, we mean that the wires are different. What EGR is talking about in human cells can be different from what speaks in the three-band panther hormone. "

The research was published in the journal Science.


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