Expression of foreign genes in animal cells

Genetic engineering in animal cells is not just a matter of high fidelity protein production. The introduction of new genetic material into a cell line is a powerful means of studying both gene expression regulation and the control of cellular processes. New cell lines can be generated by adding oncogenic DNA into normal cells by a technique known as cell immortalisation, thus providing long-term cultures of differentiated cells to act as model systems. By manipulating the genome of cells from animals and particularly from man, we can explore the complex regulation of gene expression in higher organisms.