Posted on 03/15/2019 6:16:58 AM PDT by Red Badger
When it comes to regeneration, some animals are capable of amazing feats. If you cut off a salamanders leg, it will grow back. When threatened, some geckos drop their tails to distract their predator, only to regrow them later.
Other animals take the process even further. Planarian worms, jellyfish, and sea anemones can actually regenerate their bodies after being cut in half.
Led by Assistant Professor of Organismic and Evolutionary Biology Mansi Srivastava, a team of researchers is shedding new light on how animals pull off the feat, along the way uncovering a number of DNA switches that appear to control genes for whole-body regeneration. The study is described in a March 15 paper in Science.
Using three-banded panther worms to test the process, Srivastava and Andrew Gehrke, a postdoctoral fellow working in her lab, found that a section of noncoding DNA controls the activation of a master control gene called early growth response, or EGR. Once active, EGR controls a number of other processes by switching other genes on or off.
What we found is that this one master gene comes on [and activates] genes that are turning on during regeneration, Gehrke said. Basically, whats going on is the noncoding regions are telling the coding regions to turn on or off, so a good way to think of it is as though they are switches.
For that process to work, Gehrke said, the DNA in the worms cells, which normally is tightly folded and compacted, has to change, making new areas available for activation.
A lot of those very tightly packed portions of the genome actually physically become more open, he said, because there are regulatory switches in there that have to turn genes on or off. So one of the big findings in this paper is that the genome is very dynamic and really changes during regeneration as different parts are opening and closing.
Before Gehrke and Srivastava could understand the dynamic nature of the worms genome, they had to assemble its sequence no simple feat in itself.
Thats a big part of this paper, Srivastava said. Were releasing the genome of this species, which is important because its the first from this phylum. Until now there had been no full genome sequence available.
Its also noteworthy, she added, because the three-banded panther worm represents a new model system for studying regeneration.
Previous work on other species helped us learn many things about regeneration, she said. But there are some reasons to work with these new worms. For one thing, theyre in an important phylogenetic position. So the way theyre related to other animals allows us to make statements about evolution. The other reason, she said, is, Theyre really great lab rats. I collected them in the field in Bermuda a number of years ago during my postdoc, and since weve brought them into the lab theyre amenable to a lot more tools than some other systems.
While those tools can demonstrate the dynamic nature of the genome during regeneration Gehrke was able to identify as many as 18,000 regions that change whats important, Srivastava said, is how much meaning he was able to derive from studying them. She said the results show that EGR acts like a power switch for regeneration once it is turned on, other processes can take place, but without it, nothing happens.
We were able to decrease the activity of this gene and we found that if you dont have EGR, nothing happens, Srivastava said. The animals just cant regenerate. All those downstream genes wont turn on, so the other switches dont work, and the whole house goes dark, basically.
While the study reveals new information about how the process works in worms, it also may help explain why it doesnt work in humans.
It turns out that EGR, the master gene, and the other genes that are being turned on and off downstream are present in other species, including humans, Gehrke said.
The reason we called this gene in the worms EGR is because when you look at its sequence, its similar to a gene thats already been studied in humans and other animals, Srivastava said. If you have human cells in a dish and stress them, whether its mechanically or you put toxins on them, theyll express EGR right away.
The question is, Srivastava said, If humans can turn on EGR, and not only turn it on, but do it when our cells are injured, why cant we regenerate? The answer may be that if EGR is the power switch, we think the wiring is different. What EGR is talking to in human cells may be different than what it is talking to in the three-banded panther worm, and what Andrew has done with this study is come up with a way to get at this wiring. So we want to figure out what those connections are, and then apply that to other animals, including vertebrates that can only do more limited regeneration.
Going forward, Srivastava and Gehrke said they hope to investigate whether the genetic switches activated during regeneration are the same as those used during development, and to continue working to better understand the dynamic nature of the genome.
Now that we know what the switches are for regeneration, we are looking at the switches involved in development, and whether they are the same, Srivastava said. Do you just do development over again, or is a different process involved?
The team is also working on understanding the precise ways that EGR and other genes activate the regeneration process, both for three-banded panther worms and for other species as well.
In the end, Srivastava and Gehrke said, the study highlights the value of understanding not only the genome, but all of the genome the noncoding as well as the coding portions.
Only about 2 percent of the genome makes things like proteins, Gehrke said. We wanted to know: What is the other 98 percent of the genome doing during whole-body regeneration? People have known for some time that many DNA changes that cause disease are in noncoding regions but it has been underappreciated for a process like whole-body regeneration.
I think weve only just scratched the surface, he continued. Weve looked at some of these switches, but theres a whole other aspect of how the genome is interacting on a larger scale, not just how pieces open and close. And all of that is important for turning genes on and off, so I think there are multiple layers of this regulatory nature.
Its a very natural question to look at the natural world and think, if a gecko can do this, why cant I? Srivastava said. There are many species that can regenerate, and others that cant, but it turns out if you compare genomes across all animals, most of the genes that we have are also in the three-banded panther worm so we think that some of these answers are probably not going to come from whether or not certain genes are present, but from how they are wired or networked together, and that answer can only come from the noncoding portion of the genome.
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This research was supported with funding from the Milton Fund of Harvard University, the Searle Scholars Program, the Smith Family Foundation, the National Science Foundation, the Helen Hay Whitney Foundation, the Human Frontier Science Program, the National Institutes of Health, the Biomedical Big Training Program at UC Berkeley, the Marthella Foskett Brown Chair in Biological Sciences, and the Howard Hughes Medical Institute.
Paging Dr. Curt Connors...
One. It is a fair question.
Two. What does your asking Cvengr if he is insane have to do with studies of biological properties of worms?
Three. If the existence of demons and giants is real, doesn’t that lend credence to David slaying a giant, and Christ casting out demons (to the detriment of the pigs, the ultimate unclean animal, even they were better than humans in that they simply refused to be hosts to demons!) If recognizing Biblical truths is anti-Christian in your opinion, I don’t quite know where to go with that.
My family has been able to regenerate damaged stuff for as long as I can remember. In 1960, my brother had had his thumb cur off in a car door hinge. It took him about 6 years but a new thumb grew back (It’s a half inch shorter than original but it’s a thumb). About a dozen years ago, he lost a kidney in a car wreck. Five years later, during a cat-scan they found a new kidney. As for myself, I had a heart attack 30 years ago. A 2-in section of heart muscle died. It took 5 years to regrow and come up as fully functioning. In 1974 I breathed some chemical monomer and it formed a plastic film in my lungs (I coughed blood, plastic film and lung tissue for 4 months). My lungs are perfectly normal now.
So regrowing stuff is not unheard of, it’s just rare.
If you do have this ability, don’t let a doctor know or he will want to test you and do biopsies. They biopsied my heart after the damaged part grew back. Damn, that hurt.
Thanks Red Badger.
Some people get new teeth also!.................
Have I got a guy for you...
Some people get new teeth also!.................
BTW, Regenerating is Marvel superhero Deadpool’s superpower...........
Nonsense?
No, it is very literally sensical.
Sometimes I'm amazed at how much of my body is still working.
Actually, I’ve done the same thing, from regrowing a sheared off ankle bone, to regenerating far more profoundly freaky things.
From the near-fatal accident I had in 1981, you’d never find the many [former] scars.
Stuff just grows back, with no scars.
There are many reasons I have this user name.
:)
A woman I know was hit by a drunk/drugged driver and it tore off her entire leg, including half of her pelvis.
Doctors can’t explain it but her pelvis regrew itself.
I saw the before and after xrays.
I know. That’s why I pinged you...
I’m kinda tearing up, that you bother to remember stuff about me.
I don’t deserve you.
<3
:)
Can you provide the article in the New England Journal of Medicine?
Say what?
Say what?
If such a thing happened it would be written up in a medical journal.
Can you provide the article?
I know her and saw with it my own eyes.
Are you calling me a liar?
Weird thing to say. It makes you look defensive.
I am not calling you a liar, but would have zero problem doing so if merited.
I am saying you believe something that is most likely not true.
Then my implicit reply to you consists of two words.
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