Chemically Modified Triplex-Forming Oligonucleotides for Targeted Mutagenesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for targeted genetic modification in mammalian cells are inefficient and require complex delivery systems, such as viral vectors, limiting the frequency of homologous integration and in vivo efficiency for treating genetic disorders like sickle cell anemia and cancer.
Innovation Solution
The use of high-affinity, chemically modified triplex-forming oligonucleotides (TFOs) that bind specifically to duplex DNA, stimulating mutations and recombination in target genes, thereby promoting targeted genetic changes without the need for viral vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If viral vectors are used for gene delivery, then delivery efficiency is improved, but safety and complexity increase
Solution Approach 1:
The invention extracts and eliminates the viral vector component from the gene delivery system, replacing it with non-viral TFO-based methods that achieve targeted mutagenesis without requiring complex viral delivery mechanisms
Solution Approach 2:
The invention introduces TFOs as intermediary molecules that mediate targeted genetic modification by binding to specific DNA sequences and recruiting cellular repair machinery, replacing the need for viral vectors as delivery intermediaries
2Productivity
If traditional mutagenesis methods are used, then simplicity is maintained, but mutation frequency and specificity are low
Solution Approach 1:
The invention applies local quality by designing TFOs with specific sequences that bind to particular target sites in the genome, creating localized high-concentration zones of mutagenic activity precisely where needed, thereby simultaneously improving frequency and specificity
Solution Approach 2:
The invention changes the parameters of the mutagenesis process by using chemically modified TFOs with enhanced binding affinity and stability, and by optimizing the ratio of TFO to donor DNA, thereby achieving higher mutation frequency and specificity
3Manufacturing precision
If homologous recombination is used for gene replacement, then precision is improved, but efficiency and time consumption worsen
Solution Approach 1:
The invention applies preliminary action by using TFOs to pre-bind to the target DNA sequence and recruit cellular repair machinery before the donor DNA is fully integrated, thereby priming the system for more efficient homologous recombination
Solution Approach 2:
The invention introduces TFOs as intermediary molecules that facilitate homologous recombination by binding to the target site and recruiting cellular repair proteins, thereby increasing the frequency of successful gene replacement events
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 enhances the frequency and specificity of genetic recombination, allowing for efficient in vivo and in vitro targeted mutagenesis and recombination, potentially treating genetic disorders and cancer by altering gene function without the need for viral vectors.
Implementation Method 1
oligonucleotide-directed triple helix formation has emerged as a valuable tool in molecular biology. Current knowledge suggests that oligonucleotides can bind as third strands of DNA in a sequence specific manner in the major groove in polypurine/polypyrimidine stretches in duplex DNA
Implementation Method 2
The specificity of triplex formation arises from base triplets (AAT and GGC in the purine motif) formed by hydrogen bonding; mismatches destabilize the triple helix
Data Source
AI summary
High affinity, chemically modified triplex-forming oligonucleotides (TFOs) and methods for use thereof are disclosed. TFOs are defined as triplex-forming oligonucleotides which bind as third strands to duplex DNA in a sequence specific manner. Triplex-forming oligonucleotides may be comprised of any possible combination of nucleotides and modified nucleotides. Modified nucleotides may contain chemical modifications of the heterocyclic base, sugar moiety or phosphate moiety. A high affinity oligonucleotide (Kd≦2×10−8) which forms a triple strand with a specific DNA segment of a target gene DNA is generated. It is preferable that the Kd for the high affinity oligonucleotide is below 2×10−10. The nucleotide binds or hybridizes to a target sequence within a target gene or target region of a chromosome, forming a triplex region. The binding of the oligonucleotide to the target region stimulates mutations within or adjacent to the target region using cellular DNA synthesis, recombination, and repair mechanisms. The mutation generated activates, inactivates, or alters the activity and function of the target gene.