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Using virues to transfer genes to a cell

Today in the lab I was using a virus to transfer a specific gene into a mammalian cell. For this reason, I also needed to make up a special disinfectant solution to kill the virus after the experiment. Despite this virus being genetically modified so that once it infects a cell it can no longer replicate and spread to other cells, care is still being taken to ensure the virus is properly disposed of after use. This involves immersing all tubes, pipette tips, gloves, and other consumables into a disinfectant before incineration.

Making up a disinfectant solution.
Making up a disinfectant solution.

One of my experiments involved the use of viral transduction, which is the process by which foreign DNA is introduced into a cell by a viral vector. This is because viruses have evolved specialised molecular mechanisms to efficiently transport their genomes inside the cells they infect. Viral vectors have the following properties:

Safety: Viral vectors are modified in such a way as to minimise the risk of handling them. This usually involves the deletion of a part of the viral genome critical for viral replication.

Low toxicity: The viral vector should have a minimal effect on the physiology of the cell it infects.

Stability: Some viruses are genetically unstable and can rapidly rearrange their genomes. This is detrimental to predictability and reproducibility of the work conducted using a viral vector and is avoided in their design.

Cell type specificity: Most viral vectors are engineered to infect as wide a range of cell types as possible. However, sometimes the viral receptor can be modified to target the virus to a specific cell type.

Identification: Viral vectors are often given certain genes (called markers) that help identify which cells took up the viral genes. A common marker is resistance to a certain antibiotic. The cells can then be isolated easily, as those that have not taken up the viral vector genes do not have antibiotic resistance, and so cannot grow in the presence of the antibiotic.