Trade-off between Transcriptome Plasticity and Genome Evolution in Cephalopods
Noa Liscovitch-Brauer, Shahar Alon, Hagit T. Porath, Boaz Elstein, Ron Unger, Tamar Ziv, Arie Admon, Erez Y. Levanon, Joshua J.C. Rosenthal 8, Eli Eisenberg.
Published: April 6, 2017 Accepted: March 16, 2017
Received in revised form: February 2, 2017 Received: December 5, 2016
Source/Fonte: Tom Kleindinst
• Unlike other taxa, cephalopods diversify their proteomes extensively by RNA editing
• Extensive recoding is specific to the behaviorally complex coleiods
• Unlike mammals, cephalopod recoding is evolutionarily conserved and often adaptive
• Transcriptome diversification comes at the expense of slowed-down genome evolution
RNA editing, a post-transcriptional process, allows the diversification of proteomes beyond the genomic blueprint; however it is infrequently used among animals for this purpose. Recent reports suggesting increased levels of RNA editing in squids thus raise the question of the nature and effects of these events. 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.
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