Bidirectional Constitutive Promoter for Stable Transgene Co-expression
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Solution Overview
Problem
Current methods for expressing multiple genes in transgenic plants often lead to gene silencing due to the use of identical or homologous promoters, resulting in reduced efficacy and stability of transgenic products.
Innovation Solution
The use of a bidirectional constitutive promoter from Brassica napus, combined with bicistronic organization and a 2A sequence for polyprotein processing, allows for the simultaneous expression of multiple genes using a single promoter, reducing the risk of gene silencing and promoter repetition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple genes are expressed using identical or homologous promoters, then gene expression control is simplified, but gene silencing occurs reducing transgenic stability
Solution Approach 1:
The patent merges multiple gene expression units under a single bidirectional promoter, allowing two genes to be transcribed from opposite directions. This combines what would traditionally require two separate promoters into one unified regulatory element, simplifying the overall construct while maintaining transgenic stability through reduced promoter repetition
Solution Approach 2:
The bidirectional promoter is segmented into two functional directions, with each direction driving expression of a different gene. This segmentation allows independent expression control of multiple genes while using a single promoter sequence, avoiding the homology-based silencing that occurs with identical promoters
2Adaptability or versatility
If multiple transgenes are introduced for trait stacking, then agronomic value is improved, but homology-based gene silencing increases
Solution Approach 1:
Multiple trait genes are merged into a single expression cassette under bidirectional promoter control, allowing stacking of multiple agronomic traits (such as herbicide resistance and insect resistance) while using one promoter sequence to drive all transgenes, thereby reducing homology-based silencing
Solution Approach 2:
The expression construct is designed as a composite unit combining the bidirectional promoter with multiple gene cassettes, creating a unified transgenic element that delivers multiple traits simultaneously while minimizing silencing through the use of a single promoter sequence for all transgenes
Data Source
AI summary
Provided are constructs and methods for expressing multiple genes in plant cells and/or plant tissues using a disclosed bidirectional promoter from Brassica napus or Brassica bidirectional constitutive promoter (BBCP). The constructs provided comprise at least one such bi-directional promoter linked to multiple gene expression cassettes, wherein each of the gene expression cassettes comprises at least one transgene. In some embodiments, the constructs and methods provided allow expression of genes between two and twenty.