Trade-off between transcriptome plasticity and genome evolution in cephalopods
2017-03,
Liscovitch-Brauer, Noa,
Alon, Shahar,
Porath, Hagit T.,
Elstein, Boaz,
Unger, Ron,
Ziv, Tamar,
Admon, Arie,
Levanon, Erez,
Rosenthal, Joshua J. C.,
Eisenberg, Eli
RNA editing, a post-transcriptional process, allows the diversification of proteomes beyond the
genomic blueprint; however it is infrequently used among animals. Recent reports suggesting
increased levels of RNA editing in squids thus raise the question of their nature and effects in
these organisms. We here show that RNA editing is particularly common in behaviorally
sophisticated coleoid cephalopods, with tens of thousands of evolutionarily conserved sites.
Editing is enriched in the nervous system affecting molecules pertinent for excitability and
neuronal morphology. The genomic sequence flanking editing sites is highly conserved,
suggesting that the process confers a selective advantage. Due to the large number of sites, the
surrounding conservation greatly reduces the number of mutations and genomic polymorphisms
in protein coding regions. This trade-off between genome evolution and transcriptome plasticity
highlights the importance of RNA recoding as a strategy for diversifying proteins, particularly
those associated with neural function.