Mouse Line Rederivation
Mouse Strain Rederivation Services
The WVU Barrier Facility is designed to house only “clean” or Specific Pathogen Free (SPF) mice. Mice to be housed in the barrier can be purchased from approved commercial vendors and brought directly into the barrier facility. Mice from unapproved vendors, universities or other in-house colonies may enter the barrier facility only by embryo transfer rederivation.
Rederivation by Embryo Transfer
Embryo transfer has been demonstrated to be an effective method to rederive mice known to be infected with viruses, parasites, and bacteria. Embryo transfer rederivation involves the aseptic collection of embryos from superovulated, donor females and the surgical transfer to SPF pseudo pregnant foster females for gestation to term.
Initiate a Rederivation Project
Rederivation must be approved by and coordinated with both the TACF and the Office of Laboratory Animal Resources (OLAR). A Mouse Strain Rederivation Request Form must be completed and submitted to TACF. A health and disease report for the imported or infected strain must be provided with the rederivation request form. OLAR should be contacted for details pertaining to mouse importation and to coordinate shipment and receipt of animals to be rederived.
Animals Required for Rederivation of a Single Mouse Strain
Three to five male mice are required for rederivation. The males should be older than 2 months of age and less than 6 months of age. Proven breeders are best. The males will be single housed for two to three days prior to breeding. The investigator will provide or purchase three to five females of the appropriate strain (either the mutant line or normal females of the same background) for superovulation and mating. These mice must be three to four weeks of age in order to obtain an optimal response to superovulation.
The superovulation, breeding and plug checks on donor females and embryo collection will be performed outside the barrier by OLAR, the investigator and/or research staff. In coordination with OLAR animal care staff, the females will be superovulated, bred and checked for plugs. Embryos will be harvested at 0.5 dpc and transferred into the oviduct of SPF, pseudopregnant, foster recipient females. Embryo transfer will be performed in the barrier by the TACF.
Confirmation of SPF Status
After rederived pups are born and weaned, the recipient foster females will be submitted to OLAR for testing to ascertain they are free of viruses, parasites, and pathogenic bacteria. Once the success of the rederivation procedure has been confirmed by negative test results, the mice will be released to the investigator for use. If the rederived animals are to be housed in the WVU Rodent Barrier Facility, they will be housed separate from the main rodent colony until the next sentinel testing has confirmed the SPF status of the animals. At that time, the animals will be housed with the main rodent colony in the barrier.
Time Frame for the Rederivation of Mouse Strains
This time frame represents the time needed for the rederivation of mouse strains. Upon receipt of the necessary paperwork, a production schedule will be developed and provided to the investigator. As production proceeds, the investigator will be advised of any changes to the schedule. The anticipated production timeline from initiation of the rederivation project to release of animals to the investigator is 11 to 13 weeks.
The time needed for each of the stages of rederivation is detailed below:
1 - 2 weeks
Donor females will be superovulated, bred and checked for plugs. Embryos will be harvested and transferred into the oviduct of 0.5 dpc of pseudopregnant, foster females.
Litters will be born three weeks after the date of embryo transfer.
3 - 4 weeks
Litters are weaned at 3 to 4 weeks of age. At this time the recipient foster females will be submitted to OLAR for testing.
Results of the testing of the recipient foster female are expected within two weeks. Once the success of the rederivation procedure has been confirmed, the mice will be released to the investigator for use.
8 -10 weeks
If the rederived animals are to be housed in the WVU Rodent Barrier Facility, they will be housed separate from the main rodent colony until the next sentinel testing has confirmed the SPF status of the animals. At that time, the animals will be housed with the main rodent colony in the barrier.