Moss Gene Expression via Recombination Motif Integration
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Solution Overview
Problem
Current methods for gene amplification in plant cells, such as mosses, face challenges with silencing events due to multi-copy integrations of heterologous DNA, leading to limited expression of recombinant proteins, and there is a lack of understanding about the correlation between copy number and gene expression in transgenic moss plants.
Innovation Solution
A method involving the transformation of moss plant cells with at least two heterologous nucleic acid constructs, each flanked by specific recombination sequences, which allows for increased copy number integration and enhanced protein expression by facilitating recombination events, thereby increasing the levels of heterologous protein production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple copies of heterologous DNA are integrated into moss genome to amplify gene expression, then the expression level of recombinant protein increases, but silencing events are triggered that reduce expression
Solution Approach 1:
The patent divides the heterologous DNA integration strategy into segments: instead of integrating many copies of the entire expression construct, it integrates multiple copies of smaller recombination sequence motifs (e.g., 5-20 copies of 50-200 bp sequences) that facilitate controlled recombination events. This segmentation allows amplification of the expression cassette through recombination without triggering silencing, as the integrated motifs are distributed throughout the genome rather than clustered as large multi-copy constructs.
Solution Approach 2:
The patent performs preliminary action by first integrating recombination sequence motifs into the moss genome before introducing the full expression construct. These pre-integrated motifs serve as docking sites that enable subsequent controlled recombination and amplification of the target gene, allowing the system to prepare the genomic landscape for high-expression amplification while avoiding silencing triggers.
2Manufacturing precision
If homologous recombination is used for targeted integration in moss, then precise gene insertion is achieved, but the copy number and expression amplification are limited
Solution Approach 1:
The patent merges homologous recombination and heterologous recombination mechanisms into a unified transformation strategy. It uses homologous recombination sequences for targeted integration at specific genomic loci, while simultaneously incorporating heterologous recombination motifs that enable subsequent non-homologous recombination events for amplification. This combination allows the system to achieve both precise initial insertion and subsequent expression amplification.
Solution Approach 2:
The patent introduces dynamics by creating a two-stage recombination process: first, controlled homologous recombination for precise targeted integration; second, enhanced heterologous recombination for amplification. The system transitions from a static single-mode recombination approach to a dynamic multi-stage process that adapts the recombination mechanism based on the transformation stage, enabling both precision and amplification.
3Ease of manufacture
If random integration is used for transforming moss cells, then transformation efficiency increases, but the copy number integration and expression enhancement are insufficient
Solution Approach 1:
The patent uses recombination sequence motifs as intermediary elements that mediate between random integration and targeted amplification. These motifs are randomly distributed throughout the genome through efficient transformation, but they serve as intermediaries that enable subsequent site-specific recombination events, bridging the gap between random integration efficiency and targeted amplification capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in significant increases in recombinant protein levels in moss protonema cells, overcoming the limitations of conventional transformation methods by stabilizing high copy numbers of the target gene, leading to higher protein yields.
Implementation Method 1
Moss is the only known plant system which displays a high frequency of homologous recombination. By using DNA sequences (i.e. comprised of coding or non-coding sequences) for transformation which are homologous to genomic DNA sequences of a moss can result in one or more homologous recombination events via integration of the introduced or transforming DNA into the genomic locus of the homologous DNA.
Implementation Method 2
Use of DNA sequences (i.e. comprised of coding or non-coding sequences) for transformation that lack any appreciable homology to a genomic DNA sequence of a moss can result in one or more heterologous recombination events via integration of the introduced DNA randomly into the genome.
Data Source
AI summary
A method of amplifying gene expression in a moss plant cell or moss tissue, DNA constructs therefor, moss plant cells and uses thereof for the production of protein.