Classification |
exonic circRNA (ecircRNA) |
intronic RNA (ciRNA) |
exonic-intronic circRNA (EIciRNA) |
circRNA produced by circularization of viral RNA genome, tRNA, rRNA and snRNA |
antisense circRNA originated from antisense transcripts |
Biogenesis |
exon-skipping or lariat-driven circularization |
direct back-splicing or intron-pairing-driven circularization |
RNA-binding-protein-driven circularization |
direct circularization of lariat introns |
circularization driven by tRNA splicing |
circularization driven by rRNA splicing |
Features |
high abundance and incredible diversity |
high stability |
evolutionary conservation |
tissue-specific expression |
specificity related with developmental-stage or -age expression |
competing endogenous RNAs or miRNA mediated activities |
ecircRNA mainly exists in the cytoplasm or exosomes, while EIciRNA and ciRNA mainly exist in the nucleus |
Biofunctions |
miRNA sponges |
RBP sponges |
gene transcription and expression regulators |
protein/peptide translators |
others |