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Bicknell, A.

Publications and source records attributed to Bicknell, A..

2 recordsLinked to original sources

mRNAfold: Co-optimization of Global Stability, Local Structure, and Codon Choice via Suboptimal Folding

mRNA medicines hold great promise, but designing sequences with high translation efficiency, robust in-solution stability, and manufacturability remains a major challenge due to the vast combinatorial space of synonymous coding sequences. Computational approaches such as mRNA folding algorithms have emerged as powerful tools by co-optimizing for in-solution stability and translation efficiency, yet current methods face important limitations. Here, we present "mRNAfold", an improved mRNA folding algorithm and software package that addresses these gaps by enabling efficient exploration of diverse near-optimal solutions, incorporating untranslated regions (UTRs), parallel execution, and supporting tunable control over local structural features across the mRNA. Thermodynamically optimized mRNAs from mRNAfold were more stable ({approx} 2-fold) in-solution than those generated by simple GC maximization for the same encoded protein. In addition, mRNAs designed to vary local structure near the start codon while maintaining consistent structure and codon optimality elsewhere showed a complex relationship between local structure near the start codon and protein production in cells. We observed no impact of structure in the start codon region for a set of mRNAs with high codon optimality, but it did impact protein production for a set of mRNAs with lower codon optimality. Together, these results underscore the potential of structure-aware, multi-objective design to improve mRNA medicines and offer a framework for exploring how sequence, structure, and expression are interrelated.

bioinformatics↗

Translation-dependent and independent mRNA decay occur through mutually exclusive pathways that are defined by ribosome density during T Cell activation.

mRNA translation and degradation are strongly interconnected processes that participate in the fine tuning of gene expression. Particularly, targeting mRNAs to translation-dependent degradation (TDD) could attenuate protein expression by making any increase in mRNA translation self-limiting. However, the extent to which TDD is a general mechanism for limiting protein expression is currently unknown. Here we describe a comprehensive analysis of basal and signal-induced TDD in mouse primary CD4 T cells. Our data indicate that most cellular transcripts are decayed to some extent in a translation-dependent manner, both in resting and activated cells. Our analysis further identifies the length of untranslated regions, the density of ribosomes and the GC content of the coding region as major determinants of TDD magnitude. Consistent with this, all transcripts that undergo changes in ribosome density upon T cell activation display a corresponding change in their TDD level. Surprisingly, the amplitude of translation-independent mRNA decay (TID) appears as a mirror image of TDD. Moreover, TID also responds to changes in ribosome density upon T cell activation but in the opposite direction from the one observed for TDD. Our data demonstrate a strong interconnection between mRNA translation and decay in mammalian cells. Furthermore, they indicate that ribosome density is a major determinant of the pathway by which transcripts are degraded within cells.

genomics↗