Microinjection of exogenous DNA into the pronucleus of the zygote-stage embryo allows the generation of transgenic mice by randomly integrating the DNA of interest into the host genome. The injected embryos are then transferred to a recipient female. The newborn mice are then analyzed for the presence of the transgene using PCR.

Mouse Embryonic Stem Cells (ES Cells) are electroporated with a target DNA vector to introduce specific mutations through homologous recombination into the target gene locus. The correctly modified cell clones will be frozen and expanded before being microinjected into blastocyst-stage embryos. The resulting mice from the microinjection will be chimeras, as they are generated from two different cell types: the embryo cells and the injected ES cells. The chimeric mice are then mated with Wild-type (WT) mice to allow for the transmission of the mutation to the progeny in the germline.

Rederivation of mouse lines in an SPF (Specific Pathogen-Free) environment is an important procedure for eradicating pathogens within an animal facility. Pathogens, even if they do not cause clinical diseases, can alter the physiological state of the animal and interfere with experimental analysis. Mouse lines with pathogens can be rederived into a pathogen-free state by transferring embryos from a contaminated mouse to a recipient mother in a pathogen-free area. The resulting mice from this procedure will be pathogen-free. Rederivations of mice can be performed in both heterozygous and homozygous states.

The cryopreservation of mouse lines is a widely used procedure to prevent the loss of unique mutant lines and reduce the costs of maintaining a colony that is no longer in use, following the principles of the 3Rs, thus avoiding the production of unnecessary animals. Our Facility primarily uses sperm freezing as the basic method, given its speed and the need for a reduced number of original animals for the procedure. We also offer Embryo Freezing upon request.