Journal: bioRxiv
Article Title: 3’ UTR Insertion of a Directed-Evolved RNA Element for Enhanced Translation
doi: 10.64898/2026.05.07.723449
Figure Lengend Snippet: (A), Schematic of P51 element inserted at three sites within the 3’UTR of IVT mRNA. (B), The results of P51 element inserted at three sites within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01, ****P < 0.0001, two-tailed Student’s t-test. (C), Schematic of P51 element or its truncations inserted at Site2 and Site3 within the 3’UTR of IVT mRNA. (D), The results of P51 element or its truncations inserted at Site2 and Site3 within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). (E), The results of P51t3 element inserted at Site3 within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in C2C12 and HEK293T cells transfected with 50 ng (gray) or 100 ng (blue) of the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ***P < 0.001, ****P < 0.0001, two-tailed Student’s t-test. (F), Schematic of P51 elements inserted at three sites within the 3’UTR (Moderna mRNA-1273 3’UTR) of IVT EGFP mRNA. (G), (H), The results of P51 elements inserted at three sites within the 3’UTR (Moderna mRNA-1273 3’UTR) of IVT EGFP mRNA was evaluated by fluorescence spectroscopy in HEK293T cells transfected with the respective mRNAs. Scale bar = 1000 µm. EGFP data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ****P < 0.0001, two-tailed Student’s t-test. (I), Schematic of P51t3 element inserted at Site3 within the 3’UTR of IVT Moderna mRNA-1273. (J), The results of P51t3 element inserted at Site3 within the 3’UTR of IVT Moderna mRNA-1273 was evaluated by western blot assay in HEK293T cells transfected with the mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01, two-tailed Student’s t-test. (K), Schematic of P51t3 elements inserted at four sites within the 3’UTR (BioNTech/Pfizer BNT-162b2 3’UTR) of IVT Fluc mRNA. (L), The results of P51t3 elements inserted at four sites within the 3’UTR (BioNTech/Pfizer BNT-162b2 3’UTR) of IVT Fluc mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ****P < 0.0001, two-tailed Student’s t-test. (M), Schematic of in vivo luminescence quantification. Fluc mRNAs were formulated in LNPs and equal molar quantities of mRNA-LNP complexes were administered through IM injection to male 6-8 weeks C57BL/6J mice. (N), (O), Exemplary in vivo luminescence images of mice treated with Fluc mRNA at 4, 24 and 48 h post mRNA–LNP complex administration. Color scale of the heatmaps, radiance (photons s−1 cm−2 sr−1). Luminescence was measured by integration of total flux for each mouse. Data are normalized to the mice of Ctrl group (IVT mRNA 3’UTR lacking P51t3 insertions-LNP-treated) and presented as mean ± SEM (n = 3). *P < 0.05, **P < 0.01, two-tailed Student’s t-test.
Article Snippet: In clinically relevant models, insertion of P51t3 into an mRNA containing Moderna mRNA-1273 UTRs increased spike protein expression 2–3-fold in C2C12 cells ( ).48 Similarly, in constructs mimicking BioNTech BNT162b2 UTRs, P51t3 boosted Fluc translation nearly 2-fold ( ).
Techniques: Luciferase, Transfection, Two Tailed Test, Fluorescence, Spectroscopy, Western Blot, In Vivo, Injection