Viral vectors are tools commonly used in molecular biology to bring a gene of interest or a genetic construct of interest into cells.
Viral vectors can be used both on a living organism (in vivo) and on cells in culture (in vitro). There are different types of viral vectors, with all their advantages and limitations depending on the experiments. The most commonly used are retrovirals, lentivirals, adenovirals and adeno-associated viruses. In particular, they allow the insertion of a larger or smaller piece of DNA, in a more or less stable manner, into dividing or non-dividing cells, with a higher or lower expression rate of the inserted gene. These vectors can be integrative or non-integrative, i.e. they can either integrate their DNA into the host genome, which will then be passed on to the daughter cells, or they can simply introduce the genetic material into the cell without integrating it into the DNA. The gene brought in will then express itself throughout the life of the cell and will disappear with the cell's death. Finally, in general, these vectors often incorporate a construct that distinguishes the cells that have incorporated the new DNA from the others, in order to ensure the desired viral infection.