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Safety of gene editing is closely tied to specificity.
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Careful design of gene editing tools can improve specificity and thus safety.
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A high degree of specificity is possible with the new generation of targeted nucleases.
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Assessing the impact of gene therapy tools during their design, study, and clinical use is essential.
Therapeutic Gene Editing Safety and Specificity
Section snippets
Key points
Safety
Safe manipulation of the human genome is paramount to gene therapy because the intended effect of gene therapy is a permanent modification of cell function. Thus, unintended modifications that alter cell function may have long-lasting consequences.
The last decade has seen the rapid introduction of new tools, including zinc finger nucleases, homing endonucleases, transcription activator-like effector nucleases (TALENs), and RNA-guided nucleases that allow for the targeted modification of
Specificity
Critical to the success and safety of targeted endonucleases and other forms of gene therapy is the degree of specificity that can be achieved. The random integration events that occur with retroviral gene delivery demonstrate the danger of gene therapy in the absence of high degrees of specificity. New generations of targeted endonucleases, including zinc finger nucleases, TALENs, and CRISPR/CRISPR-associated endonuclease (Cas) 9, each have unique mechanisms for binding to specific genomic
Summary
Learning from the challenges of the first gene therapy trials, a large emphasis has been placed on improved specificity to achieve safety. The new generation of targeted nucleases has made the possibility of precise genetic manipulation a reality. The purpose of this article is not to endorse a particular platform over another. Each has their merits and all have the potential for safe and effective therapeutic application. Importantly, large-scale cross-platform comparisons of safety and
Acknowledgment
The authors would like to thank Jackie Morton, Seattle Children's Hospital Librarian, for her assistance in conducting a literature search for this submission.
References (32)
- et al.
Frequent endonuclease cleavage at off-target locations in vivo
Mol Ther
(2010) - et al.
Genome-wide translocation sequencing reveals mechanisms of chromosome breaks and rearrangements in B cells
Cell
(2011) - et al.
Genome-editing technologies for gene and cell therapy
Mol Ther J Am Soc Gene Ther
(2016) - et al.
CRISPR-based adaptive and heritable immunity in prokaryotes
Trends Biochem Sci
(2009) In vivo tissue-tropism of adeno-associated viral vectors
Curr Opin Virol
(2016)- et al.
T lymphocyte-directed gene therapy for ADA− SCID: initial trial results after 4 years
Science
(1995) - et al.
An online bioinformatics tool predicts zinc finger and TALE nuclease off-target cleavage
Nucleic Acids Res
(2014) - Optimized CRISPR design. Available at:...
- et al.
DNA targeting specificity of RNA-guided Cas9 nucleases
Nat Biotechnol
(2013) - et al.
Systematic evolution of ligands by exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase
Science
(1990)
A genome-wide analysis of Cas9 binding specificity using ChIP-seq and targeted sequence capture
Nucleic Acids Res
GUIDE-seq enables genome-wide profiling of off-target cleavage by CRISPR-Cas nucleases
Nat Biotechnol
Improving the safety of cell therapy products by suicide gene transfer
Front Pharmacol
Statement on NIH funding of research using gene-editing technologies in human embryos
Natl Inst Health NIH
Human genome editing: science, ethics, and governance
Targeted chromosomal cleavage and mutagenesis in Drosophila using zinc-finger nucleases
Genetics
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