Citrus Tissue-Specific Promoters for Targeted Gene Expression
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Solution Overview
Problem
There is a need for novel transcription and translation regulatory elements that can direct high-level expression of heterologous DNA specifically in root tissue cells, phloem tissue cells, or fruit and abscission zone tissue cells in dicotyledonous plants, as existing promoters lack specificity and efficiency for these tissues.
Innovation Solution
The development of expression vectors and cassettes containing specific 5' transcription regulatory elements, such as SCAmpPs 302z, 289s, and 396s, which are predominantly active in root, phloem, and fruit/abscission zone tissues, respectively, along with translation regulatory elements, to achieve tissue-specific expression and translation of polynucleotides in genetically altered plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constitutive promoters are used to continuously express genes, then transcription efficiency is improved, but tissue specificity is lost
Solution Approach 1:
The patent applies local quality by using tissue-specific promoters (root hair promoters, phloem promoters, fruit/abscission zone promoters) instead of constitutive promoters. Each promoter is selectively active in specific plant tissues, enabling localized gene expression where needed while maintaining high transcription efficiency in those specific tissues.
Solution Approach 2:
The patent changes the parameter of promoter specificity by identifying and utilizing naturally occurring tissue-specific promoters from plant genes. These promoters have inherent tissue-specificity parameters that are leveraged to drive heterologous gene expression in specific tissues, resolving the contradiction between efficiency and specificity.
2Adaptability or versatility
If existing promoters are used for heterologous DNA expression, then general expression capability is achieved, but tissue-specific expression efficiency in root, phloem, or fruit tissues is insufficient
Solution Approach 1:
The patent addresses this contradiction by selecting promoters with locally optimized quality for specific tissues. Root hair promoters (e.g., AtRH5, LAC14), phloem promoters (e.g., CsSUS1p, CsPP2p), and fruit/abscission zone promoters (e.g., CsACS3p, CsETR3p) are chosen based on their demonstrated high efficiency in their respective target tissues, thereby achieving both versatility and high productivity.
3Manufacturing precision
If novel tissue-specific promoters are developed, then tissue-specific expression precision is improved, but the complexity of identifying and characterizing appropriate promoters increases
Solution Approach 1:
The patent applies preliminary action by pre-identifying and characterizing a library of tissue-specific promoters from plant genes before they are needed for heterologous expression. The promoters have been previously validated for their tissue-specific activity patterns, so when a specific tissue-targeted expression is needed, the appropriate promoter is already available and characterized, reducing the complexity of on-demand promoter identification.
Data Source
AI summary
Expression vectors and expression cassettes containing a tissue specific 5′ transcription regulatory element, optionally linked to a translation regulatory element, optionally linked to an intron transcription regulatory element, operably linked to a heterologous polynucleotide encoding a protein or RNA of interest are described. The 5′ transcription regulatory elements control expression in root tissue cells, phloem tissue cells, or fruit and/or abscission zone tissue cells. These sequences are obtained from citrus plants. Methods of use of these expression vectors and expression cassettes are described, as well as genetically altered plants and parts thereof that contain these expression vectors and/or cassettes.