Transgenic animals inducible promoters

Overexpression of the EGF receptor (or any of its ligands), can also induce cancer in both cell lines and transgenic animal models. Monoclonal antibodies capable of blocking receptor activity can promote tumour regression in mice suffering from various carcinomas. A direct correlation also exists between elevated EGF receptor numbers and a shorter patient survival span in the case of several forms of breast, oesophageal, bladder and squamous cell carcinomas. 

In some circumstances the introduction of a cloning vector into a host cell is a trivial process. For example, phage vectors are designed so they introduce recombinant DNA in an infective process called transfection, and some bacteria take up plasmids unaided. However, most host cells must be induced to take up foreign DNA. Several methods are used. In some prokaryotic and eukaryotic cells, the addition of Ca2+ to the medium promotes uptake. In others, a process called electroporation, in which cells are treated with an electric current, is used. One of the most effective methods for transforming animal and plant cells is the direct microinjection of genetic material. Transgenic animals, for example, are created by the microinjection of recombinant DNA into fertilized ova. 

Mendelsohn, C., Ruberte, E., Le Meur, M., Morriss-Kay, G., Chambon, P. 1991. Developmental analysis of the retinoic acid-inducible RAR-beta 2 promoter in transgenic animals. Development 113, 723-734. 

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