offers rederivations of a particular strain of mice
or rats into A-rated facilities on campus. Whether an investigator needs to recover a strain which
previously had been cryopreserved, needs to rederive a strain from embryos shipped from a source
outside the university, or a strain within the university that carries
unwanted pathogens, we will work with the investigator to generate and/or
collect embryos for transfer into pathogen-free pseudopregnant recipients.
basic steps in a rederivation project are:
of embryos by mating superovulated females to males
of embryos from females
of embryos into pseudopregnant females
to rederivation, the investigator will need to meet with TAF staff to determine the specific needs of the
investigator, develop a strategy and schedule for rederivation, and discuss
fees. Please contact Kathy Krentz (email@example.com) or (608) 890-3785 to schedule an initial meeting.
Generation, Collection and Transfers
- Meet with Kathy Krentz to discuss rederivation strategy
- Amend animal protocol to include IP injections of hormones
- complete a billing request form
a previously cryopreserved strain is being recovered from liquid nitrogen,
straws are thawed and embryos transferred into pseudopregnant ICR (for
mice) and SD (for rats) recipients.
For projects involving the transfer
of a strain from another university, the investigator will generate embryos
and ship these embryos to TAF via overnight delivery. The TAF staff
will work with the investigator to provide the necessary guidance so that
the investigator can superovulate, mate, collect embryos and prepare the embryos for delivery to the
For projects involving the rederivation
of pathogen-carrying strains from within the university, we will provide
investigators with protocols, hormones and training (if necessary) so
that they can superovulate and dissect reproductive tracts from the animals, thereby allowing
us to avoid contact with donor animals. We will collect the embryos
from the reproductive tracts and transfer them into pseudopregant ICR
(for mice) and SD (for rats) recipients. The number of transfers
completed depends on the number of good quality embryos collected.
In all situations, pups will
be born about three weeks later and weaned three weeks after that. Recipient
moms will be screened for pathogen status by serological testing. The
pups will be transferred to the investigator as soon as serology results
indicate the recipient mom is pathogen-free and the animal transfer form
has been completed by the investigator and an LAR veterinarian from the
When rederiving strains, investigators
are charged based on the number of embryo transfers performed.