Usually described as elusive, squids are highly skillful animals. They have bilateral symmetry, gills that are used for breathing, and skin covered with chromatophores, pigment-containing and light-reflecting cells through which they can camouflage to the environment.
Now, scientists have discovered another surprising feature of squids. Not only they can edit their RNA or genetic instructions within the nucleus of their neurons but also within the axon, which are the neural projections that transmit electrical impulses to other neurons.
DNA and RNA are the most important molecules in cell biology, responsible for the storage and reading of genetic information that underpins all life. While DNA replicates and stores genetic information, RNA converts the genetic information contained within DNA to a format used to build proteins.
Back in 2015, a group of researchers discovered that squids were able to change their RNA instructions, fine-tuning the type of proteins to be produced. Now, they were able to dig deeper into their work and observe the edits outside the nucleus of the cell of the squids.
“We thought all the RNA editing happened in the nucleus, and then the modified messenger RNAs are exported out to the cell,” says Rosenthal, senior author. “Now we are showing that squid can modify the RNAs out in the periphery of the cell. That means, theoretically, they can modify protein function to meet the localized demands of the cell.”
In the past, Rosenthal and his group of researchers also worked in cuttlefish and octopus, which they discovered also rely on the editing of RNA to diversify the proteins they produce in the nervous system. Alongside the squid, this group of animals is known for its sophisticated behavior.
The findings could have implications not only for squids but also for humans, as the axon dysfunction is associated with neurological disorders. Researchers hope the study will help biotech companies use the RNA editing process in humans for therapeutic benefits.
"The idea that genetic information can be differentially edited within a cell is novel and extends our ideas about how a single blueprint of genetic information can give rise to spatial complexity. Such a process could fine-tune protein function to help meet the specific physiological demands of the different cellular region," the researchers wrote.
The paper was published in Nucleic Acids Research.