Complex Octopus Brain Linked to MicroRNA

 A group of researchers examined the brain of octopuses, and it was found that their intelligence can be connected to their RNA. After examining the mRNA in 18 tissues, including parts of the brain, it was found that octopus’ mRNA does not have unusual features, like the scientists expected, except for having unusually long tails. The tail of mRNA helps in exporting the mRNA from the nucleus to the cytoplasm, a longer tail could give extra control to the mRNA. MicroRNA are molecules that can mark mRNA for disposal or prevent the message from being translated. It was found that octopuses have 164 miRNA genes, similar to chicken. It is very uncommon for an invertebrate to have this many miRNA. It was observed that 34/43 of the miRNA families in octopuses were concentrated in neural tissue, leading to the conclusion that this miRNA has a big effect on the intelligence of the species. Because of the miRNA similarity to vertebrate species, which also have complex brains, it can be inferred that miRNAs are linked to the evolution of complex animal brains.

Sources: 

https://www.science.org/doi/10.1126/sciadv.add9938

https://journals.biologists.com/jeb/article/226/3/JEB244991/286807/Did-microRNAs-make-octopuses-smart

Octopuses and Cephalopods Can Edit Their RNA

New research by Joshua Rosenthal and Eli Eisenberg identified that octopuses and other cephalopods adjust to environmental differences like temperatures by editing their RNA. Previous research has found that cells have the capacity to swap one member of the four letter genetic code, Adenosine, for a substitute molecule, Inosine. This protein altering is called A-to-I and it was found in octopuses. Researchers used the California two-spot octopus and acclimated them to their natural range of temperatures in the cold and warmer tanks. When examining their RNA they found increases at 13,285 sites in the cold tanks where the one letter change alters the protein. In the warmer tanks they found 550 sites. With the help of other collaborators at the University of Michigan and Texas Tech University, they were able to identify proteins that were altered when the processes of RNA editing occurred. One of the proteins was kinesin-1, which changes the rate at which this molecule travels. This then alters the responsiveness of a protein called synaptotagmin that allows for communication between neurons. 

Link 1: https://news.uchicago.edu/story/octopuses-other-cephalopods-can-adjust-cold-editing-their-rna

Link 2: https://new.nsf.gov/news/masters-acclimation-octopuses-adjust-cold-editing