Transgenic Mice

Transgenic mice provide for the exogenous expression of a protein in some or all tissues as one method of assessing gene function. Transgenic mice are produced by microinjection of DNA into the pronuclei of fertilized single-cell mouse embryos.

Transgene integration can be random or targeted via regulatory elements, typically with multiple copies of the transgene integrating into a single chromosomal locus in the embryo. If integration takes place prior to the first nuclear division, then all cells in the founder animal will carry the transgene. Random or targeted gene insertions can be achieved through this technology.

Microinjected embryos are surgically placed into the oviducts of recipient female mice and allowed to develop to term. The offspring representing potential founders are given to the investigator after weaning.

The investigator provides:

• Purified DNA fragment free of vector sequence DNA (It is required that the DNA be purified according to our protocol).
• A map of the fragment, and expected phenotype.
• A gel photograph to document the purity of the DNA.

The facility provides:

• Microinjection of the DNA fragment into pronuclei of a standard hybrid mouse strain (C57BL/6J X CBA/J). A non-standard strain (e.g. C57BL6/J) can be used at the investigator's request with extra charges.
• Implantation of at least 100 injected eggs or at least 3 transgenic foundersoffspring (whichever comes first).
• If no transgenic mice are obtained after 100-egg implantation (this is due to toxicity associated with inpure DNA), the charge will incur. The investigator will then be requested to repurify the DNA. A second round of trial will be scheduled without charges. If, however, the second round fails, a meeting will be scheduled to determine the best course of action.

Note: Animal costs and per diem care of mice used in meeting services from the Transgenic facility will be billed to investigators according to AHR's standard rates.