RT Journal Article
SR Electronic
T1 Circular RNA repertoires are associated with evolutionarily young transposable elements
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.03.01.433421
DO 10.1101/2021.03.01.433421
A1 Franziska Gruhl
A1 Peggy Janich
A1 Henrik Kaessmann
A1 David Gatfield
YR 2021
UL http://biorxiv.org/content/early/2021/03/01/2021.03.01.433421.abstract
AB Circular RNAs (circRNAs) are found across eukaryotes and can function in post-transcriptional gene regulation. Their biogenesis through a circle-forming backsplicing reaction is facilitated by reverse-complementary repetitive sequences promoting pre-mRNA folding. Orthologous genes from which circRNAs arise, overall contain more strongly conserved splice sites and exons than other genes, yet it remains unclear to what extent this conservation reflects purifying selection acting on the circRNAs themselves. Our analyses of circRNA repertoires across five species representing three mammalian lineages (marsupials, eutherians: rodents, primates) reveal that surprisingly few circRNAs arise from orthologous exonic loci across different species. Even the circRNAs from the orthologous loci are associated with young, recently active and species-specific transposable elements, rather than with common, ancient transposon integration events. These observations suggest that many circRNAs emerged convergently during evolution – as a byproduct of splicing in orthologs prone to transposable element insertion. Overall, our findings argue against widespread functional circRNA conservation.Competing Interest StatementThe authors have declared no competing interest.