Boston University Medical Campus
Transgenic Facility

Re-derivation

Rederivation by Embryo Transfer

The transgenic core performs rederivations by embryo transfer. The embryos from animals, which are carrying or suspected of carrying pathogenic agents are removed and transferred into pathogen free animals. This method of embryo transfer is the only one, which will guarantee the removal of adventitious agents from your colony giving you pathogen free animals to work with. The transgenic core recommends this service for any line that has tested positive for pathogens, as well as any new lines being imported from other institutions to BU. Following is a schematic for rederivation via embryo transfer.

• Schematic for re-derivation from live mice (e,g., infected with a pathogen):

  Day 1– Inject hormones to donor females(PMS).

  Day 3– Inject hormones to donor females(HCG) and set up with males. Set up pathogen-free females with vasectomized males.

  Day 4– Check females for vaginal plug to confirm mating. Isolate embryos from infected females, treat them to disinfect and transfer them into pathogen free females.

  Day 24– Pathogen free litters are born.

  Day 38– Eye bleeds, foster mothers to confirm removal of adventitious agents.

  Day 45– Wean pathogen free pups.

• Schematic for re-derivation from frozen embryos:

  Day 1– Set up clean females with vasectomized males.

  Day 2– Check females for vaginal plug to confirm mating.

  Day 3– Thaw 8 cell embryos.

  Day 4– Transfer blastocyst stage embryos into clean females.

  Day 24– Pathogen free litters are born.

  Day 45– Wean pathogen free pups.