The octopus brain is unlike anything we know. Octopuses rank among Earth’s most intelligent creatures. They boast a neuron count similar to dogs. But, over half of these neurons reside in their eight arms, not in a central brain. This neural setup sets them apart.
Now, researchers have discovered something even more peculiar. Octopuses can rewrite their RNA in reaction to temperature shifts. This action is akin to humans adjusting outfits according to the weather.
By editing their RNA, octopuses change how their cells produce proteins. This flexibility may help them cope with seasonal temperature shifts. Joshua Rosenthal, a lead biologist, calls this ability “extraordinary.”
RNA Editing: A Temporary Genetic Makeover
Humans undergo RNA editing, but it’s limited. It affects protein production in fewer than 3% of our genes. In contrast, advanced cephalopods can adjust most neural proteins through RNA editing. Motivated by this disparity, scientists sought the driving forces behind cephalopod RNA editing. They prioritized temperature, given its frequent fluctuations.
They gathered California two-spot octopuses, familiarizing them with varying water temperatures. Weeks later, they probed 60,000 RNA editing sites in the octopus genomes. A third of these sites showed changes occurring astonishingly fast, from mere hours to a few days. Eli Eisenberg, another lead researcher, found the widespread changes unexpected.
Most of these changes manifested in cold conditions. They influenced proteins crucial for cell membrane health, neuron signal transmission, controlled cell death, and neuron calcium binding. Although these protein variants arise from RNA editing, Eisenberg admits that the complete adaptive benefits remain elusive.
Wild octopuses from both summer and winter displayed similar RNA changes. This solidified the belief in temperature as a major influencer in RNA editing for octopuses.
Protective RNA Editing for the Octopus Brain
Octopuses can’t control their body temperature like mammals can. Thus, scientists theorize that RNA editing acts as a protective mechanism against temperature shifts. Eisenberg elaborates that octopuses might opt for protein versions optimal for prevailing conditions. Such adaptive behavior is absent in mammals.
Heather Hundley, an external biologist, praised this groundbreaking study. She highlighted its potential in reshaping our understanding of RNA editing as a dynamic regulatory process in response to environmental changes.
The future beckons more investigations. The team plans to examine other potential RNA editing triggers in the octopus brain. Factors like pH, oxygen levels, or even social interactions might hold further insights. With each revelation, the octopus brain continues to astound the scientific community.
Source: “Octopuses Redesign Their Own Brain When They Get Chilly”‘ — Scientific American
