The ocean is home to many different species in the world. Oftentimes, this home can be very cold place. Species across the ocean all have different ways of adapting to this cold : Mammals like seals stay warm by enveloping themselves in a layer of thick fur and blubber, for example. However, Cephalopods, such as Squids and Octopuses, don’t have the luxury of any thick fur or blubber. So how can they adapt to living in the cold ocean?
Recent research has shown that some Octopuses and Squid adapt to the cold temperatures by altering their bodies on the molecular level.
One researcher reports June 8 in Cell has shown that when water temperatures inside the tank of a California two-spot Octopus drops below 10 degrees Celsius, this Octopus changes what proteins they produce by editing tons of their own RNA.
A molecular neurobiologist at the Marine Biological Laboratory in Woods hole, Mass, Joshua Rosenthal, says that this incredibly high level of molecular editing can also help octopuses’ brains function when temperatures plunge (as most of the this molecular editing occurs in the nervous system).
Scientists have known for decades that Cephalopods, such as Octopus, are masters of RNA. Only about 3% of mRNA in humans have the ability to be edited. Octopuses and Squids, on the other hand, take this editing to another level changing thousands of mRNA.
What scientist didn’t know about Cephalopods yet is what sets off the editing of the mRNA. Research now suggests that temperature is potentially the trigger. Rosenthal and his colleagues set off to test this potential trigger. They either heated or cooled the tank temperature of a California two spotted octopus and looked at what proteins it produced in its brain. They noticed that heating set off very minimal mRNA editing, while cool temperatures edited over 20,000 mRNA sites.
This relates to what we learn in AP Biology as we learned about the process of protein synthesis within cells. We learned that the nucleus of a eukaryotic cell (such as the cells of a animal like an Octopus) contain chromosomes consisting of DNA. This DNA holds the instructions to synthesizing proteins, and mRNA is formed and transports these instructions. The mRNA leaves the nucleus through the nuclear pores and finds the ribosomes in the cytosol or on the Rough Endoplasmic Reticulum to carry out the instructions the mRNA holds and enter the next stage of the protein synthesis. What we learn here, however, is that it is not always a direct path for the mRNA to the ribosomes. Especially in these Octopuses, the mRNA is edited and the instructions they carry get changed and with this they get sent to different Ribosomes where different proteins from the ones originally instructed are formed.
This discovery of Cephalopods high levels of molecular editing is a very fascinating insight as it shows us the that cell activities aren’t as straight forward as sometimes they may seem. As humans, we often live in suitable living conditions and our cells create proteins simply based off the instructions of our DNA. We carry out the process that is typically learned in AP biology. But for species such as the California two- spotted Octopus, this simplistic process is not always followed. The instructions held by the mRNA are edited creating different proteins. This makes it clear that Octopuses are not only different from many species on the outside, but on a molecular level too.
I have often wondered how unique species such as the Octopus are so different from us, not only in ways we can see but also on a internal or molecular level too! Do you know of any other unique species that are also this molecularly distinct from humans?
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