Genome editing or gene editing refers to a group of technologies that scientists use to manipulate virtually any genomic DNA of different organisms including viruses, bacteria, plants and animals.
Recent development of gene editing technologies has enabled more efficient and precise change of targeted genes, creation of isogenic cell lines and animal models for the study of human disease, and new possibilities for human gene therapies.
DNA Editing and RNA Editing
Gene editing usually refers to the modification of genomic DNA, which results in a permanent change of genetic information.
The genomic information contained in DNA cannot be translated into functional protein and needs a intermediate message called Messenger RNA (mRNA) is a single-stranded RNA molecule that is complementary to one strand of a gene. Unlike DNA editing, the effects of RNA editing are reversible and dose-dependent because cells are constantly produce new copies of mRNA to generate proteins.
Scientists are developing both DNA and RNA editing technologies for different applications and potential gene therapies for human diseases.
Evolution of DNA Editing Technology
The gene editing usually starts from a double-strand break (DSB) at the targeted genomic DNA to trigger one of two endogenous cellular DNA repair pathways: either the non-homologous end joining (NHEJ) pathway, which is useful for gene knockout by the introduction of insertion or deletions (indels), or homology-directed repair (HDR), which is useful for gene knock-in by the integration of a donor sequence at the target site.
Initial DNA editing uses naturally occurring nucleases like meganucleases to introduce a DSB for gene-editing applications. In recent years, three major gene editing technologies have been developed and tested in human clinical trials: (1) zinc-finger nucleases (ZFNs), (2) transcription activator-like effector nucleases (TALENs), (3) clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (CRISPR/Cas9) technologies.
RNA Based Editing Technology: LEAPER™
LEAPER™ refers to the use of endogenous ADAR to programmatically edit RNA (ADAR is the abbreviation of adenosine deaminase acting on RNA, i.e. the RNA adenosine deaminase).
Based on the natural mechanisms in cells, the specific adenine nucleotide on the target RNA can be edited in an efficient and accurate way by recruiting the endogenous proteins of cells with only a specially-designed guide RNA transferred, without introducing any exogenous effector protein.
Gene Editing Therapeutics
Many diseases can be traced back to differences in the body's genetic code. Gene editing therapy can fix these problems at the source, that is to say, different from small molecular or biologics, gene editing therapy addesses the underlying diseases cause.
Scientists are developing ex vivo or in vivo gene editing therapies for cancer, rare diseases, cardiovascular diseases, ophthalmic diseases and many other diseases.
Data related to the treatment of single-gene inheritance diseases will lay foundation for providing more treatments and health benefits.