Gene delivery by retroviruses.

Gene delivery by retroviruses is an easy and safe tool to stably over express a gene of interest and determine its role in a cell model. The gene of interest is cloned into the multiple cloning site of a retroviral vector that also contains a packaging signal and an antibiotic resistance marker for selection. Packaging cell lines, transfected with a retroviral vector containing the gene of interest or with a control vector, produce retroviral RNA packaged into infectious, replication incompetent virus. This is a consequence of the stable integration of the viral genes necessary for particle formation and replication into the packaging cell genome. Retrovirus-containing conditioned medium from packaging cells is used to transduce target cells. After antibiotic selection, the target cells are tested for overexpression of the gene of interest and its biological effects.