Molecular diversity through RNA editing: a balancing act

Abstract

RNA editing by adenosine deamination fuels the generation of RNA and protein diversity in eukaryotes, particularly in higher organisms. This includes the recoding of translated exons, widespread editing of retrotransposon-derived repeat elements and sequence modification of miRNA transcripts. Such changes can bring about specific amino acid substitutions, alternative splicing and changes in gene expression levels. Although the overall prevalence of A-to-I editing and its specific functional impact on many of the affected genes are not yet known, the importance of balancing RNA modification levels across time and space is becoming increasingly evident. In particular, transcriptome instabilities in form of too much or too little RNA editing activity, or misguided editing manifest in several human disease phenotypes which disrupt that balance.

Comprehensive analysis of RNA-Seq data reveals extensive RNA editing in a human transcriptome

“…On the basis of its overabundance in repetitive Alu elements and the brain transcriptome [1][2][3] , RNA editing has been viewed as a key determinant in primate evolution and the development of higher brain functions 4 . Many outstanding questions on the extent and consequences of RNA editing in humans remain unanswered, despite extensive documentation of edited sites through bioinformatics approaches [5][6][7][8][9] and the reported roles of editing in altering genetic messages and other post-transcriptional events such as RNA splicing and miRNA regulation 2,[10][11][12] . Global and unequivocal identification of RNA editing targets represents a critical first step in further understanding this post-transcriptional modification.…”

Extensive Loss of RNA Editing Sites in Rapidly Evolving Silene Mitochondrial Genomes: Selectionvs. Retroprocessing as the Driving Force

“…Various adaptive effects of RNA editing have been proposed, including a role in gene regulation (Hirose et al 1999;Farajollahi and Maas 2010), maintenance of alternative functional protein isoforms (Gott 2003;Farajollahi and Maas 2010), generation of genetic variation (Tillich et al 2006;Gommans et al 2009), optimization of genomic GC content (Jobson and Qiu 2008), nuclear control of selfish organelle genes (Burt and Trivers 2006), and mutational buffering (Borner et al 1997). In humans, there is evidence for divergent functional roles for products of the edited and unedited forms of apolipoprotein B (Powell et al 1987), but there is little evidence for the aforementioned adaptive mechanisms in plant organelles.…”

RNA EDITING IN Calotropis procera MITOCHONDRIAL NADHDEHYDROGENASE SUBUNIT 3 GENE

“…NA editing refers to posttranscriptional alterations of RNA molecules through insertion, deletion, or modification of nucleotides, not including RNA splicing, capping, or polyadenylation (Nishikura, 2006;Farajollahi and Maas, 2010). RNA Editing was discovered for the first time in trypanosome mitochondria (Benne et al, 1986).…”