3' UTR sequences for stabilization of RNA
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Solution Overview
Problem
Current RNA-based cancer vaccines face challenges in achieving high stability and translation efficiency due to the short half-life of RNA and difficulties in cloning and transcription processes, particularly with sequences like the human beta-globin 3'-UTR, which can lead to recombination and mispriming issues during PCR-based amplification.
Innovation Solution
The use of modified RNA sequences in the 3'-untranslated region (UTR) and poly(A) sequence, including an open-ended poly(A) sequence achieved through type IIS restriction cleavage, enhances stability and translation efficiency by introducing a type IIS restriction cleavage site into expression vectors, allowing for linearization within the polyadenyl cassette and optional disruption with a random nucleotide sequence, thereby improving RNA stability and translational efficiency in dendritic cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two consecutive copies of the human beta-globin 3'-UTR sequence are used in the plasmid DNA, then RNA stability and translational efficiency are improved, but recombination during propagation in E. coli and mispriming during PCR-based amplification occur
Solution Approach 1:
The patent applies parameter changes by substituting the human beta-globin 3'-UTR sequence with an optimized 3'-UTR sequence that maintains the stabilizing function while eliminating recombination-prone regions. The optimized sequence preserves key functional elements (polyadenylation signal, stabilizing motifs) while changing the nucleotide composition to prevent mispriming and recombination events during cloning and propagation.
Solution Approach 2:
The patent extracts the essential stabilizing function from the human beta-globin 3'-UTR sequence without retaining the problematic sequence elements. By identifying and preserving only the critical functional motifs (such as the polyadenylation signal AAUAAA and downstream stabilizing elements) while removing recombination-prone regions, the invention achieves RNA stability without the harmful side effects of recombination and mispriming.
2Ease of manufacture
If conventional type II restriction enzymes are used for linearization downstream of the polyadenyl cassette, then the circular plasmid is linearized for in vitro transcription, but the poly(A) sequence is masked or extended by remaining nucleotides
Solution Approach 1:
The patent introduces a type IIS restriction enzyme (such as BsmBI or BsaI) as an intermediary tool that performs linearization at a precise location within the polyadenyl cassette. These enzymes recognize a specific DNA sequence and cleave at a defined distance from the recognition site, allowing exact positioning of the linearization cut to ensure the poly(A) sequence remains accurate and properly positioned in the final transcript.
Solution Approach 2:
The patent changes the enzymatic parameter from conventional type II restriction enzymes to type IIS restriction enzymes, which have distinct cleavage characteristics. Type IIS enzymes cleave outside their recognition site at a predictable distance, enabling precise control over where linearization occurs. This parameter change allows linearization within the polyadenyl cassette without masking or extending the poly(A) sequence, achieving both ease of manufacture and manufacturing precision.
Data Source
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AI summary
The present invention relates to stabilization of RNA, in particular mRNA, and an increase in mRNA translation. The present invention particularly relates to a modification of RNA, in particular in vitro-transcribed RNA, resulting in increased transcript stability and/or translation efficiency. According to the invention, it was demonstrated that certain sequences in the 3'- untranslated region (UTR) of an RNA molecule improve stability and translation efficiency.