In molecular biology, a vector is a vehicle that is used to deliver genetic material to a target cell via horizontal gene transfer
There are several methods for transferring genetic material, but all mechanisms can be classed as either viral or non-viral
Non-Viral Delivery
A commonly used vector is a plasmid – a circular DNA molecule capable of self-replication and autonomous protein expression
Plasmids can be introduced to target cells by a variety of means, including:
- Electroporation – An electric current is applied to make temporary holes in the cell membrane
- Heat shocking – Thermal energy is used to briefly destabilise the cell membrane to allow for vector entry
- Particle bombardment – DNA-coated particles are shot into the cells by a gene gun
- Microinjection – A glass micropipette is used to inject the vector directly into the cell
- Lipofection – The vector is transferred within a liposome (a vesicle capable of fusion with the cell membrane)
Viral Delivery
The insertion of a viral vector into a cell is called transduction and utilise the ability of a virus to inject its DNA into a host cell
Viruses integrate their DNA directly into the host genome, which can have both beneficial and detrimental consequences
- The advantage of this practice is that protein synthesis will be driven by endogenous expression patterns
- A disadvantage of this practice is that there is a risk the random insertion into the genome will abrogate key host genes
Viruses can have either a DNA genome (adenovirus) or an RNA genome (retrovirus)
- Retroviruses use an enzyme called reverse transcriptase to convert the RNA sequence into a DNA copy prior to integration
Overview of Viral Delivery (Adenovirus)
