Artificial 5′-UTR Leader Sequence for Plant Protein Expression
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Solution Overview
Problem
Current methods for designing high-efficiency 5′-UTR leader sequences for recombinant protein expression in plants face challenges due to sequence variability, length constraints, and the presence of A/T-rich motifs and ATT triplets, which can lead to unpredictable interactions and secondary structures, affecting translation efficiency.
Innovation Solution
The development of artificial DNA sequences with optimized 5′-UTR leader regions that exclude A/T-rich motifs and ATT triplets, incorporating poly(CAA) and poly(CT) regions, and a Kozak consensus sequence to enhance translation initiation, while maintaining a low GC content and avoiding secondary structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If natural leader sequences are used for recombinant protein expression, then translation efficiency can be improved, but sequence variability and A/T-rich motifs cause unpredictable interactions and secondary structures
Solution Approach 1:
The patent applies parameter changes by systematically modifying the nucleotide composition of leader sequences. Specifically, it adjusts the GC content to optimize ranges (30-70%, preferably 40-60%), controls the length within 100-120 bp, and regulates A/T-rich motif content to prevent secondary structures. These parameter optimizations enable reliable prediction and consistent improvement of translation efficiency without the variability problems of natural sequences.
Solution Approach 2:
The patent extracts and removes problematic elements from natural leader sequences, specifically eliminating A/T-rich motifs and ATT triplets that cause unpredictable secondary structures and interactions. By taking out these harmful components while retaining the essential leader function, the invention achieves reliable and predictable translation efficiency improvement.
2Productivity
If the leader region length is increased to include more functional elements, then translation efficiency can be improved, but the frequency of spontaneous dissociation of the 43S complex increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the leader region length within 100-120 bp. This optimal length allows inclusion of necessary functional elements (Kozak consensus sequence, poly(CAA) regions, poly(CT) regions) while preventing excessive length that would cause 43S complex dissociation. The balanced parameter selection resolves the contradiction between incorporating functional elements and maintaining complex stability.
3Stability of the object's composition
If the leader region contains G/C-rich sequences to prevent secondary structures, then structural stability improves, but palindrome sequences may form causing resolution problems
Solution Approach 1:
The patent applies parameter changes by optimizing GC content within specific ranges (30-70%, preferably 40-60%) rather than maximizing it. This moderate GC content provides sufficient structural stability while avoiding the formation of stable palindrome sequences and secondary structures that would be problematic for eIF4A resolution. The balanced parameter approach prevents both structural instability and harmful secondary structure formation.
Data Source
AI summary
Artificial DNA of a 5′-UTR leader region, which artificial DNA is effective in increasing the expression of recombinant proteins in plants, and comprises, along the 5′→3′ direction, an Inr initiator site and a Kozak or Kozak-like consensus sequence, and also comprises, between the Inr initiator site and the Kozak or Kozak-like consensus sequence, a plurality of poly(CAA) and a plurality of poly(CT) regions, in the same number as the poly(CAA) regions wherein at least one, optionally each one, poly(CAA) region, in the 5′→3′ direction, is upstream of a poly(CT) region and at least one poly(CAA) region, in the 5′→3′ direction, is contiguous with a poly(CT) region, wherein the artificial DNA provides the absence of A/T-rich motifs, the absence of trinucleotide elements ATT, the absence of trinucleotide elements CTG and the absence of homopolymeric tracts, that is, sequences consisting of more than 3, optionally more than 4, identical nucleotides.