We recently reported a blue light-activatable photocaging group to control CFPS, which acts orthogonally to UV light. By combining a blue light-activatable (bLA) mV DNA template with the uvLA-V3 ASO, we envisaged a system where transcription could be selectively turned ON with blue light and translation turned OFF with UV light (Fig. ). We initially tested this in an IVT reaction using the bLA-mV DNA template in the presence of RNase H and uvLA-V3 (Supplementary Fig. ). Following blue light irradiation, we observed an increasing amount of mV-mRNA produced over three hours, as measured on agarose gel electrophoresis, similar to the amount produced from a non-modified DNA template (Supplementary Fig. ). The IVT reactions were then incubated for a further hour with or without UV illumination. When irradiated with UV light the mRNA was almost completely degraded in one hour, due to activation of uvLA-V3. Without UV illumination, no degradation was observed, demonstrating uvLA-V3 was not activated.