Intro to gene therapy NOTE

What is gene therapy?

A treatment of a disease by introduction of genetic material into cells of an affected patient to modify specific gene expression.

What genetic issues can gene therapy help with?

Cystic Fibrosis, Severe combined immunodeficiency ‘bubble boy disease’, and Haemophilia.

What is transduction in gene therapy?

A form of transportation of gene to a patient through infection.

What is transfection in gene therapy?

A form of transportation of gene to a patient via plasmid.

What genetic material is used in gene therapy?

DNA, RNA, and oligonucleotides.

What is somatic gene therapy?

Aimed at somatic cells and is currently allowed.

What is germ line therapy?

Specific oocyte pronucleus injection or perivitelline injection, currently not allowed due to ethical debates.

How is instructed DNA manufactured?

Like a drug with strict requirements.

What is pronuclear injection?

A direct injection of DNA into the nucleus used to make transgenic animals.

What equipment is used for pronuclear injection?

A micropipette and an inverted microscope with 200x magnification.

What is nuclear transplantation?

Also known as the Dolly technique, it allows for correct homologous recombination but has risks that are considered unacceptable.

What are the advantages of non-viral vectors in gene therapy?

Unlimited DNA-packaging capacity, low toxicity, low immunogenicity, non-infectious, easy chemical production, easily modifiable.

What are the disadvantages of non-viral vectors?

Long process of optimization to reach high efficiency, low efficiency, transient persistence.

What are the advantages of adenovirus vectors?

Suitable for in vivo use especially in lungs, very high virus titres, well understood biology.

What are the disadvantages of adenovirus vectors?

No integration into host genome, virus proteins can cause dose-dependent inflammatory reactions.

What are the advantages of adeno-associated vectors?

Small genome, long-term gene expression, non-pathogenic, humans are natural hosts.

What are the disadvantages of adeno-associated vectors?

Limited capacity for foreign genes, requires adenovirus as helper for replication.

What are the advantages of retroviral vectors?

Good insert capacity for foreign DNA, stable integration into host genome, high efficiency of transfer.

What are the disadvantages of retroviral vectors?

Infects only dividing cells, random integration may interfere with cellular genes.May recombine to replication competent virus. Often only transient expression. Relatively low virus titre

What does CRISPR-9 gene editing do?

Changes the basis of current gene therapy approaches as it does not function via gene addition.

What is induced pluripotent stem cell technology?

Reversing a skin cell to a stem cell.

What are the issues with somatic gene therapy?

May reduce efficiency of transfer and cause harmful effects from ectopic expression.

What are the targets of gene therapy for cancer?

To kill off cancer cells via suicide genes or immune stimulation.

What is the theoretical best strategy to avoid random integration?

Homologous recombination or autonomously replicating episomal elements.