PGASO Method for Simultaneous Multi-Gene Insertion in Yeast
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Solution Overview
Problem
Current methods for large-scale genomic engineering of cells are inefficient in simultaneously introducing multiple genes into a genome, particularly in organisms other than well-studied hosts like Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae, and there is a need for improved techniques to engineer yeast strains for cellulosic biofuel production.
Innovation Solution
The Promoter-based Gene Assembly and Simultaneous Overexpression (PGASO) method allows for the efficient insertion of multiple gene cassettes in a predetermined order into a cell's genome using specific upstream promoter sequences without linker sequences, enabling co-expression of genes at different expression levels and applicability to any host via homologous recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional gene transformation methods are used to introduce multiple genes into a genome, then each gene must be inserted separately through multiple steps, but this process is time-consuming and inefficient
Solution Approach 1:
The patent merges multiple separate gene transformation steps into a single simultaneous transformation step. By designing a multi-gene cassette system where multiple genes are introduced together through one transformation event, the method eliminates the need for sequential gene insertion, thereby dramatically improving transformation efficiency and reducing time loss.
Solution Approach 2:
The patent applies preliminary action by pre-assembling multiple genes into a unified cassette structure before transformation. The genes are arranged in a predetermined order within the cassette with proper regulatory elements, so that when transformation occurs, all genes are introduced and positioned correctly in a single step, avoiding time-consuming post-transformation manipulation.
2Device complexity
If genes are inserted using traditional cloning methods with linker sequences, then gene assembly is possible, but the use of linker sequences adds unnecessary complexity and affects expression control
Solution Approach 1:
The patent extracts and removes linker sequences from the gene assembly process. By eliminating linkers and using direct promoter-gene-cassette structures with overlapping sequences for recombination, the method simplifies the assembly architecture while maintaining the ability to control gene expression through promoter selection and cassette design.
Solution Approach 2:
The patent creates a universal cassette system that can accommodate multiple genes with different expression requirements. The standardized cassette structure with modular promoters and overlapping sequences serves multiple functions: it enables simultaneous insertion, maintains predetermined gene order, allows independent expression control, and works across different genetic contexts without requiring gene-specific linkers.
3Productivity
If multiple genes with individual promoters are introduced separately, then expression levels can be controlled, but the process requires multiple transformation steps and is inefficient
Solution Approach 1:
The patent combines multiple genes with their individual promoters into a single transformable cassette unit. This merging allows all genes to be introduced simultaneously in one transformation step while preserving the ability to control each gene's expression through its associated promoter, thus achieving both speed and adaptability.
Solution Approach 2:
The patent segments the cassette into modular units where each gene is associated with its own promoter and terminator elements. This segmentation within the unified cassette structure enables independent expression control for each gene while maintaining the efficiency of simultaneous introduction through single transformation.
4Productivity
If genome engineering methods are developed for well-studied hosts like E. coli and S. cerevisiae, then efficient gene manipulation is achieved, but these methods are not applicable to other organisms
Solution Approach 1:
The patent develops a universal genome engineering method that functions across different host organisms. By using homologous recombination-based cassette integration that does not rely on host-specific machinery, the system achieves both efficient gene manipulation and broad applicability to various organisms including those that are less-studied.
Solution Approach 2:
The patent adapts the gene cassette system to different organisms by adjusting parameters such as promoter selection and cassette design rather than fundamentally changing the core methodology. This allows the same basic approach to work efficiently across diverse hosts with varying genetic characteristics.
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
PGASO enables the simultaneous transformation of multiple genes into a genome in one step, optimizing enzyme combinations and expression profiles, enhancing cellulolytic efficiency in yeast strains like Kluyveromyces marxianus for biofuel production.
Implementation Method 1
the plurality of nucleic acid molecules join together in the predetermined order via homologous recombination between the overlapping sequences and the promoter sequences, and are inserted into the genome via homologous recombination
Data Source
AI summary
Described herein is an engineered Kluyveromyces marxianus cell, the cell comprising in its genome: (i) two different nucleic acid molecules that each contain a promoter operably linked to a gene encoding a functional enzyme, and (ii) a selection nucleic acid molecule that contains a promoter operably linked to a gene encoding a selectable marker, wherein all of the nucleic acids molecules of (i) and (ii) are in tandem and the engineered cell expresses all of the proteins encoded by the genes of (i) and (ii).