Knock-out cells

Knock-out cells are cells in which researchers have inactivated, or "knocked out," an existing gene by replacing it or disrupting it with an artificial piece of DNA. The loss of gene activity often causes changes in the cells' phenotype, which includes appearance and other observable physical and biochemical characteristics.

Knocking out the activity of a gene provides valuable clues about what that gene normally does. Using cell lines from humans or species with high similarity gives researchers information that can be used to better understand how a similar gene may cause or contribute to diseases. Knockout cells also offer a biological context in which drugs and other therapies can be developed and tested.