A flexible, high-throughput system for studying live mRNA translation with HiBiT technology.

HiBiT is an engineered luciferase's 11-amino-acid component that can be introduced as a tag at either terminus of a protein of interest. When the LgBiT component and a substrate are present, HiBiT and LgBiT dimerize forming a functional luciferase. The HiBiT technology has been extensively used for high-throughput protein turnover studies in cells. Here, we have adapted the use of the HiBiT technology to quantify messenger RNA (mRNA) translation temporally in vitro in the rabbit reticulocyte system and in cellulo in HEK293 cells constitutively expressing LgBiT. The assay system can uniquely detect differences in cap, 5'UTR, modified nucleotide composition, coding sequence optimization and poly(A) length, and their effects on mRNA translation over time. Importantly, using these assays we established the optimal mRNA composition varied depending on the encoded protein of interest, highlighting the importance of screening methods tailored to the protein of interest, and not reliant on reporter proteins. Our findings demonstrated that HiBiT can be easily and readily adapted to monitor real-time mRNA translation in live cells and offers a novel and highly favourable method for the development of mRNA-based therapeutics.