Submission + - Octopuses Can Rewire Their 'Brains' By Editing Their Own RNA On the Fly (sciencealert.com)
An anonymous reader writes: Octopuses have found an incredible way to protect the more delicate features of their nervous system against radically changing temperatures. When conditions fluctuate, they can rapidly recode key proteins in their nerve cells, ensuring critical neurological activities remain functional when temperatures drop dramatically. How do they do it? By deploying a rare superpower – editing their RNA on the fly, an ability found in some species of octopuses, squids and cuttlefish. It's an unusual strategy, but it appears to be an effective one, and scientists believe that it may be widely adopted throughout the world of cephalopods. [...]
Their subjects were California two-spot octopuses (Octopus bimaculoides), whose entire genome was first sequenced in 2005, making it a useful animal for understanding genetic changes. The researchers acclimated these octopuses to warm water at 22 degrees Celsius (71.6 Fahrenheit) or much chillier water at 13 degrees Celsius (55.4 Fahrenheit), then compared their genetic information against the database genome. They specifically looked at over 60,000 known editing sites, and what they found was astonishing. "Temperature-sensitive editing occurred at about one third of our sites – over 20,000 individual places – so this is not something that happens here or there; this is a global phenomenon," says physicist Eli Eisenberg of Tel-Aviv University, co-senior author of the paper. "But that being said, it does not happen equally: proteins that are edited tend to be neural proteins, and almost all sites that are temperature sensitive are more highly edited in the cold."
So the editing seemed to be in response to acclimating to cold, rather than warm water, affecting neural proteins that, specifically, are sensitive to cold temperatures. And tests of structural proteins critical for the function of the octopus nervous system – kinesin and synaptotagmin – found that the changes wrought would have an impact on their function. It was possible that what the team observed was the result of being in a lab, so they caught wild California two-spot octopuses and Verrill's two-spot octopuses (Octopus bimaculatus) in Summer and Winter and checked their genomes, too. These octopuses had similar patterns of RNA editing that suggested they were optimizing their function for the current temperature conditions.
The team also tested to see how quickly the changes take place. They tweaked the temperature of an octopus's tank from 14 degrees Celsius to 24 degrees Celsius or vice versa, tuning the temperature up or down by 0.5 degrees increments over the course of 20 hours. They tested the extent of RNA editing in each octopus just before starting the temperature change, just after, and four days later. It happens very quickly, the researchers found. "We had no real idea how quickly this can occur: whether it takes weeks or hours," explains [marine biologist Matthew Birk of the Marine Biological Laboratory and Saint Francis University]. "We could see significant changes in less than a day, and within four days, they were at the new steady-state levels that you find them in after a month."
Their subjects were California two-spot octopuses (Octopus bimaculoides), whose entire genome was first sequenced in 2005, making it a useful animal for understanding genetic changes. The researchers acclimated these octopuses to warm water at 22 degrees Celsius (71.6 Fahrenheit) or much chillier water at 13 degrees Celsius (55.4 Fahrenheit), then compared their genetic information against the database genome. They specifically looked at over 60,000 known editing sites, and what they found was astonishing. "Temperature-sensitive editing occurred at about one third of our sites – over 20,000 individual places – so this is not something that happens here or there; this is a global phenomenon," says physicist Eli Eisenberg of Tel-Aviv University, co-senior author of the paper. "But that being said, it does not happen equally: proteins that are edited tend to be neural proteins, and almost all sites that are temperature sensitive are more highly edited in the cold."
So the editing seemed to be in response to acclimating to cold, rather than warm water, affecting neural proteins that, specifically, are sensitive to cold temperatures. And tests of structural proteins critical for the function of the octopus nervous system – kinesin and synaptotagmin – found that the changes wrought would have an impact on their function. It was possible that what the team observed was the result of being in a lab, so they caught wild California two-spot octopuses and Verrill's two-spot octopuses (Octopus bimaculatus) in Summer and Winter and checked their genomes, too. These octopuses had similar patterns of RNA editing that suggested they were optimizing their function for the current temperature conditions.
The team also tested to see how quickly the changes take place. They tweaked the temperature of an octopus's tank from 14 degrees Celsius to 24 degrees Celsius or vice versa, tuning the temperature up or down by 0.5 degrees increments over the course of 20 hours. They tested the extent of RNA editing in each octopus just before starting the temperature change, just after, and four days later. It happens very quickly, the researchers found. "We had no real idea how quickly this can occur: whether it takes weeks or hours," explains [marine biologist Matthew Birk of the Marine Biological Laboratory and Saint Francis University]. "We could see significant changes in less than a day, and within four days, they were at the new steady-state levels that you find them in after a month."
