Research focus

​The Transgenic Mice Core Facility (TMCF) of the DMBR was established in 2004 to cater to the needs of DMBR investigators. The mission of the TMCF is to provide efficient and economic access to transgenic animals and related technologies.
 
Summary of services

Gene targeting in ES-cells
Embryonic Stem (ES) cells are electroporated with a targeting vector designed to introduce a specific mutation in the mouse genome. After antibiotic selection, surviving colonies are picked and expanded for screening and freezing. To generate transgenic mice over-expressing a gene of interest, dedicated ES cells and targeting vectors are available to specifically introduce the transgene in the Hprt or the Rosa locus.

Generation of chimeras
Correctly targeted ES cells are introduced in an early mouse embryo. This can be done by injecting the ES cells into blastocysts or by aggregating ES cell clumps with morulas; the ES cells assist in the formation of the fetus. The resulting mouse is a chimera composed of two cell types: cells derived from the embryo and those derived from the introduced ES cells. The chimeric mice are mated with wild-type mice to transmit the desired mutation from the chimeric to the offspring.

Rederivation of mouse strains
The presence of any type of mouse pathogen (whether it causes clinical disease or not), changes the physiology of the mouse, which can lead to false experimental results. Mouse strains harboring pathogens can be ‘rederived’ to a pathogen-free status by transferring preimplantation embryos from a contaminated mouse to a pathogen-free foster mother. The resulting pups will then also be pathogen-free.

Speed cryopreservation
The purpose of embryo freezing is to protect against the loss of valuable, unique mouse stocks through breeding failure or disease, and to eliminate the cost of maintaining mouse lines that are not in use. Speed cryopreservation combines IVF with cryopreservation of the resulting two-cell stage embryos. Frozen embryos are maintained in liquid nitrogen tanks.

Derivation of ES cell lines
ES cells are derived from the inner cell mass of the blastocyst. ES cells can multiply 'indefinitely' and are undifferentiated. Under the right conditions, they can differentiate into all specialized cells of the body. The genetic background of the ES cell line is an important issue when making a genetically targeted mouse and when performing in vitro experiments, and so the TMCF attempts to derive ES cells from all desired mouse strains.