Figure 3.

Assessment of cSAA products and yield from PIE construct E1 point mutants. (A) Pre-circularization secondary structure of the streptavidin aptamer-T4 td fusion RNA (SAA), with intron segments E1, E2, IG sequence, and splice sites (lightning bolts) also depicted. (B) Transcription/circularization products from WT (native E1, E2, IG) and NEG (mutant E1) constructs fractionated over a 4% agarose gel. The migration position of the circRNA product (cSAA) is indicated. (C and D) Mutant descriptions, including predicted base-pairing with IG, cSAA yield, and synthesis profiles for the indicated WT and E1 and E2 point mutant constructs. Fractional cSAA yields (arrows) relative to total RNA in each reaction are normalized to WT fractional yields (100%) in the same experiment.