How does gene therapy work?
Vectors



What is a vector?
Gene therapy products work by introducing genetic material into the nucleus of the cell. In order to introduce the genetic material, scientists need a delivery system that can transport the gene, nuclease, or short hairpin RNA (shRNA) to the nucleus of a human cell. The vehicle that carries this genetic material is known as a vector. Like a microscopic delivery truck, the vector can transport and deliver genetic material to target cells or locations in the person’s genome.
There are two types of vectors, viral and non-viral. Viral vectors are currently a delivery vehicle used in FDA-approved gene therapies. Non-viral techniques are currently being studied as a safe and effective way to deliver genetic material to cells for therapeutic effect.
Gene therapy products work by introducing genetic material into the nucleus of the cell. In order to introduce the genetic material, scientists need a delivery system that can transport the gene, nuclease, or short hairpin RNA (shRNA) to the nucleus of a human cell. The vehicle that carries this genetic material is known as a vector. Like a microscopic delivery truck, the vector can transport and deliver genetic material to target cells or locations in the person’s genome.
There are two types of vectors, viral and non-viral. Viral vectors are currently a delivery vehicle used in FDA-approved gene therapies. Non-viral techniques are currently being studied as a safe and effective way to deliver genetic material to cells for therapeutic effect.
Gene therapy products work by introducing Genetic materialrefers to materials that play a fundamental role in determining the structure and nature of a cell; these include the nucleus, mitochondria, and cytoplasm
See glossary for more terms > into the nucleus of the cell. In order to introduce the genetic material, scientists need a delivery system that can transport the Geneinstructions made of DNA used to create the proteins the body needs to function
See glossary for more terms >, Nucleasean enzyme that divides nucleic acid into nucleotides and other products
See glossary for more terms >, or Short hairpin RNA (shRNA)an artificial RNA molecule that enables gene supression
See glossary for more terms > to the nucleus of a human cell. The vehicle that carries this genetic material is known as a Vectora delivery system used to introduce genetic material into the nucleus
See glossary for more terms >. Like a microscopic delivery truck, the vector can transport and deliver genetic material to target cells or locations in the person’s genome.1, 2
There are two types of vectors, Viral vectora way to deliver genetic material to a cell using the blueprint of a virus as a guide; it may be used to carry genes and change mutated cells to healthy ones
See glossary for more terms > and Non-viral vectora way to deliver genetic material to a cell that is not based on a virus
See glossary for more terms >. Viral vectors are currently a delivery vehicle used in FDA-approved gene therapies. Non-viral techniques are currently being studied as a safe and effective way to deliver genetic material to cells for therapeutic effect.1, 3, 4

Viral and non-viral vectors
Viral vector gene delivery has been utilized in a number of gene therapies due to the virus’ natural ability to access the cells of the body.1,5
Non-viral vectors are currently being evaluated for long-term expression of the therapeutic genetic material. The most actively researched non-viral vectors include Chemical disruption vectora type of vector that is typically designed to target specific cells and increase the delivery of genetic material to cytosol or nucleus
See glossary for more terms >, Electroporationthe use of an electric field to make a cell more permeable which allows the delivery of genetic material
See glossary for more terms >, and Polymer-based vectorpolymers are one of the substances used to create chemical vectors. These complexes protect DNA and facilitate cell uptake and intracellular delivery
See glossary for more terms >.4
Why are viruses used to deliver gene therapy?
Viruses are used as models or blueprints to create viral vectors. This is because viruses are good at entering the nucleus and delivering instructions to a host cell—much like a delivery truck delivers packages to people. Scientists have actually mapped the complete genetic material (genome) of many viruses. They are able to isolate the helpful elements of a virus’ genome—the delivery truck components—and create them on their own as the starting point for a viral vector. To create a viral vector, only a few parts of the virus are used. These parts alone are not adequate to cause viral infection.
See glossary for more terms >) of many viruses. They are able to isolate the helpful elements of a virus’ genome—the delivery truck components—and create them on their own as the starting point for a viral vector. To create a viral vector, only a few parts of the virus are used. These parts alone are not adequate to cause viral infection.1
While a number of viral blueprints exist, the choice is based on characteristics such as duration of Gene expressionwhen the information encoded in a gene is used and expressed as an effect or trait
See glossary for more terms >, packaging capacity, target cells, and Immunogenicitythe degree to which a substance triggers an immune response
See glossary for more terms >.1 Before they can be used, Viral vectora way to deliver genetic material to a cell using the blueprint of a virus as a guide; it may be used to carry genes and change mutated cells to healthy ones
See glossary for more terms > are reviewed by the FDA.1, 6
The final viral vector is like a delivery truck that has updated its contents. The delivery truck just needs the correct address to deliver the new load. Once the genetic material carried by the vector has been delivered to the host cell/tissue, it can help deliver the transgene (or gene of interest) to the nucleus. Once in the nucleus, the transgene can provide instructions to produce the essential functional protein that is needed. After delivery, they are naturally degraded by the host cell/tissue.1

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References
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