Fig. 3: IRES truncations and the secondary structure of the IRES-coding sequence junction affect circRNA translation.
From: Engineering circular RNA for enhanced protein production
a, NanoLuc activity at 24 hours after transfection of HeLa cells with circRNAs containing deletions of successive IRES domains starting from the 5′ end. Secondary structure and truncation points are indicated on the diagram. NanoLuc activity was normalized to constitutive firefly luciferase activity from the same sample and then divided by values from mock transfection. Data are mean ± s.e.m. for n = 3 biological replicates. b, NanoLuc activity at 24 hours after transfection of HeLa cells with circRNAs containing deletions of individual IRES domains. NanoLuc activity was normalized to constitutive firefly luciferase activity from the same sample and then divided by values from mock transfection. Data are mean ± s.e.m. for n = 3 biological replicates. c, NanoLuc activity at 24 hours after transfection of HeLa cells with circRNAs containing successive 10-nt deletions starting from the 3′ end of the IRES, immediately before the AUG start codon. NanoLuc activity was normalized to constitutive firefly luciferase activity from the same sample and then divided by values from mock transfection. Data are mean ± s.e.m. for n = 3 biological replicates. d, Correlations between the indicated properties and NanoLuc activity at 24 hours after transfection of HeLa cells with circRNAs containing different N-terminal leader sequences between the AUG start codon and NanoLuc reporter. NanoLuc activity was normalized to constitutive firefly luciferase activity from the same sample and then divided by values from mock transfection. Data are mean ± s.e.m. for n = 3 biological replicates. D, domain; WT, wild-type.
