RNA molecules, methods of producing circular RNA, and treatment methods

An isolated cell comprising a synthetic circular RNA molecule comprising:

• a first ligation sequence, a synthetic effector molecule positioned 3′ to the first ligation sequence, and a second ligation sequence positioned 3′ to the synthetic effector molecule, wherein the first and second ligation sequences are ligated together, wherein a 3′ portion of the first ligation sequence is complementary to a 5′ portion of the second ligation sequence, wherein prior to the ligation, a 5′-OH end of the first ligation sequence is produced by autocatalyzed cleavage of a 5′ first self-cleaving ribozyme of an exogenous, synthetic linear RNA molecule in the cell and the 2′,3′-cyclic phosphate end of the second ligation sequence is produced by autocatalyzed cleavage of a 3′ second self-cleaving ribozyme of the exogenous, synthetic linear RNA molecule,
• wherein the exogenous, synthetic linear RNA molecule comprises:
• a portion of the first ligation sequence complementary to a portion of the 5′ first ribozyme and a portion of the second ligation sequence complementary to a portion of the 3′ second ribozyme, such that the portion of the first ligation sequence complementary to the portion of the 5′ first ribozyme is complementary to the portion of the second ligation sequence complementary to the portion of the 3′ second ribozyme.