Table 1.

Functions of circRNAs.

Function	Example	Ref.
miRNA sponge	circ-HIPK3 circ-PRKCI	[16,17]
Histone methylation	Circ-ANRIL	[18]
Protein sponge	circ-Foxo3	[19]
RNA maturation	circ-ANRIL	[20]
RNAP II elongation	circ-EIF3J circ-PAIP2	[21]
Translation regulator	circ-PABPN1	[22]
Alternative splicing	circ-Mbl	[23]
Protein translation (including m6A-driven)	circ-ZNF609	[24,25]