The ocean can be a cold place to call home. Mammals like seals stay warm by boxing themselves in a cocoon of thick fur and blubber. Cephalopods — the group of substantially ultra-smart mollusks that include squid and octopuses—don't have that luxury.
Rather, some octopuses and squid manage by altering their bodies' molecular positions.
When water temperatures inside their tank dropped by 10 degrees Celsius, California two-spotted octopuses( Octopus bimaculoides) changed what proteins they produced by editing vast swathes of their own RNA, experimenters report June 8 in Cell.
The “astonishing high situations” of molecular editing, most of which occur in the nervous system, could help octopuses’ smarts serve when temperatures plunge, says Joshua Rosenthal, a molecular neurobiologist at the Marine Biological Laboratory in Woods Hole,Mass.
Another study in Cell, also published on June 8, set up an analogous effect of temperature on RNA editing in California request squid( Doryteuthis iridescent).
Scientists have known for over a decade that cephalopods are masters of RNA editing( SN5/19/23). DNA holds the instructions to make proteins, one of the crucial structural blocks of the body. But it relies on runner RNA, or mRNA, to shuttle those instructions out of the cell nexus and to the proteins responsible for erecting other proteins.
Generally, mRNA faithfully clones these instructions. But occasionally, mRNA is edited, which can change how those proteins are made or indeed what proteins are made. For example, about 3 percent of mRNA in humans has the capacity to be edited, though indeed, smaller amounts are edited.
Octopuses and squid take this editing to the extreme, changing thousands of mRNAs.
What sets off this storm of editing isn’t always egregious. A former exploration suggested that temperature might be a detector. To test this, Rosenthal and his associates either heated or cooled the tanks of octopuses and looked to see what proteins they produced in their brains. While heat set off veritably little editing, octopuses that endured cool temperatures altered over 20,000 mRNA spots, which changed around a third of the instructions for making proteins.
This fury of editing started in the space of only a few hours, presumably changing the geste
of octopus smarts. For example, the platoon set up that mRNA editing caused kinesis, a protein that shuttles weight in whim-wham cells, to decelerate its movement. Why this happens is unknown, but it might help the weight-carrying protein harmonise its movements with other processes in the cell if they too become sluggish, Rosenthal says.
Cold-exposed squid also edited their kinesis; however, in their case, the changes helped the proteins move lesser distances inside cells, says Kavita Rangan, a molecular biologist at the University of California, San Diego, who conducted the squid study.
Former studies have shown that conditions can be favourable for RNA editing. This “truly amazing body of work” shows that environmental changes, like temperature, can also shape mRNA editing, says Heather Huntley, an RNA experimenter at Indiana University Bloomington who wasn't involved with the exploration.
Octopuses have long captured the public imagination through their intelligence and disguise, says octopus study coauthor Matthew Berk, a cephalopod biologist at Saint Francis University in Loretto, Pennsylvania. “We'’re now learning that they're strange not just on the outside but down to the molecular position.”
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