Intelligent octopuses adjust to cold by simply tweaking their RNA

For this study, the team studied the California two-spot octopuses to better understand the link between temperature variations and nervous system activity. 
Mrigakshi Dixit
California two spot octopus (Octopus bimaculoides).
California two spot octopus (Octopus bimaculoides).

Tom Kleindinst 

Octopuses adapt to the chilly conditions in a unique way by merely tweaking their RNA. 

The Marine Biological Laboratory (MBL) and Tel Aviv University researchers made this fresh and surprising discovery. They carried out a series of experiments to see how octopuses react to seasonal changes. 

“We’re used to thinking all living things are preprogrammed from birth with a certain set of instructions. The idea the environment can influence that genetic information, as we’ve shown in cephalopods, is a new concept,” said Joshua Rosenthal of MBL in an official release published in EurekAlert.

The study experiment 

For this study, the team studied the California two-spot octopuses (Octopus bimaculoides) to better understand the link between temperature variations and nervous system activity. 

This octopus species is often found off the coasts of California and Mexico. Scientists had already sequenced their whole genome, which provided a significant edge for this study. 

The octopuses were initially acclimated to warm temperatures (22 degrees Celsius), then to cold water (13 degrees Celsius). The team monitored their RNA activity simultaneously. 

The RNA transcripts of cold- and warm-acclimated octopuses were matched to the sequenced genome after many weeks of monitoring. This aided in identifying RNA editing locations. 

Tinkering of RNA

When octopuses were exposed to cold water tanks, the researchers saw an increase in RNA editing. Protein-altering activity increased at up to 13,000 RNA sites in the nervous systems of the animals. The RNA tinkering happened at 550 such locations for those in the warm tanks.

“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,” said co-senior author Eli Eisenberg of Tel-Aviv University.

Eisenberg added, “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.”

The scientists emphasize that the RNA editing changes are only temporary, implying that these animals employ this method to adapt to seasonal temperature changes. However, this type of RNA editing doesn’t work for rapid ones associated with traveling from warmer surface water down to cooler depths. 

The researchers also revealed that RNA editing affected the activity of two proteins required for octopus brain function. This rewiring most likely enhances the brain activities of octopuses in such conditions.

 “The first protein, kinesin-1, ferries cargo along the long branches of neurons. RNA editing, they found, changes the rate at which this molecule travels. Likewise, it alters the responsiveness of a protein called synaptotagmin that enables the communication between neurons,” mentioned the release. 

The scientists speculate that these soft-bodied cephalopods may be employing genetic tinkering to adapt to changes other than seasonal variations.

They could be using this mechanism to perform complex behavior, for instance, solve mechanical puzzles, and mimic colors and textures to camouflage themselves.