Targeted Insertion Sites in Maize Genome
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Solution Overview
Problem
Current methods for introducing a DNA of interest into a maize cell are inefficient and often result in random insertion, which can lead to unstable expression and agronomic performance issues in transgenic plants.
Innovation Solution
The method involves identifying and targeting specific ideal genomic loci within the maize genome for the integration of a DNA of interest, using a combination of nucleic acid molecules encoding site-specific nucleases and expression cassettes to facilitate targeted recombination and stable expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random insertion methods are used to introduce DNA into maize cells, then the transformation process is simple, but the expression stability and agronomic performance are poor
Solution Approach 1:
The patent applies preliminary action by pre-identifying and characterizing ideal genomic target sites with favorable properties (unique sequences, open chromatin, active transcription) before introducing the DNA of interest. This preliminary characterization of target loci ensures that subsequent targeted insertion will result in stable expression and good agronomic performance, resolving the contradiction between simple transformation methods and reliable expression outcomes.
Solution Approach 2:
The patent uses site-specific nucleases (such as ZFNs, TALENs, or CRISPR-Cas systems) as intermediary tools to mediate between the DNA of interest and the maize genome. These nucleases target specific pre-identified genomic loci and facilitate precise insertion of the transgene, thereby improving expression stability without requiring complex random screening processes.
2Reliability
If targeted insertion into predetermined loci is implemented, then expression stability improves, but the complexity of identifying and targeting specific sites increases
Solution Approach 1:
The patent performs preliminary identification and characterization of ideal genomic target sites by analyzing genome sequences to locate regions with unique nucleotide sequences, open chromatin structure, and active transcription. This pre-screening and characterization of target loci simplifies the overall process by providing a ready list of favorable insertion sites before the actual transformation occurs.
Solution Approach 2:
The patent changes key parameters of target site selection by focusing on specific genomic characteristics: unique sequence identity (to avoid repetitive regions), chromatin accessibility (open vs. closed structure), and transcriptional activity (active vs. inactive regions). By defining these specific parameter criteria, the patent simplifies target identification while ensuring stable transgene expression.
3Manufacturing precision
If extensive screening is performed to identify high-quality transgenic events, then expression quality improves, but time and resource consumption increase
Solution Approach 1:
The patent performs preliminary selection of ideal genomic target sites with known favorable properties for transgene expression before transformation. By pre-characterizing target loci with unique sequences, open chromatin, and active transcription, the patent ensures that inserted transgenes will inherently exhibit high expression quality, thereby eliminating the need for extensive post-transformation screening.
Solution Approach 2:
The patent converts the potential harm of random insertion (unpredictable expression) into a benefit by using site-specific nucleases to target predetermined favorable loci. This approach transforms the challenge of insertion randomness into an advantage where each insertion occurs at a pre-validated optimal site, guaranteeing high expression quality without time-consuming screening.
4Manufacturing precision
If site-specific nucleases are used for targeted cleavage, then integration precision improves, but the complexity of nuclease design and delivery increases
Solution Approach 1:
The patent employs site-specific nucleases (ZFNs, TALENs, or CRISPR-Cas systems) as intermediary molecules that mediate between the predetermined genomic target sites and the DNA of interest. These nucleases are designed to recognize and bind to specific DNA sequences at the pre-identified target loci, creating controlled breaks that facilitate precise insertion of the transgene, thereby achieving high integration precision.
Solution Approach 2:
The patent changes the precision parameter by using nucleases with programmable specificity. Each nuclease is designed to recognize a unique DNA sequence at the target locus, and by adjusting the guide RNA or DNA-binding domain, the targeting specificity can be precisely controlled. This parameter adjustment allows high integration precision without requiring complex delivery systems.
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 allows for the precise integration of a DNA of interest into predetermined genomic loci, enhancing the stability and expression of transgenes, and reducing the need for extensive screening to identify high-quality transgenic events.
Implementation Method 1
a second nucleic acid molecule comprising a nucleotide sequence encoding a nuclease for site-directed cleavage at a genomic nuclease cleavage site
Data Source
AI summary
The present invention relates to methods and compositions for targeted insertion of polynucleotide molecules into ideal target sites in the genome of a maize plant. The present invention relates to maize recombinant molecules comprising heterologous sequences and also to methods of integrating a DNA of interest into a target maize genomic locus in a maize genome. The present invention also relates to regenerated maize plants or plant parts comprising the recombinant molecules and/or a DNA of interest.