The Core is able to resuscitate a mouse line using frozen embryos or sperm provided by investigators at any time.
Embryos or sperm received from outside institutions will be thawed according to the protocol provided by the supplier; recovery of viable embryos cannot be guaranteed.We have routinely thawed frozen embryos using protocols accompanying the embryos, and implanted all recovered embryos to produce pups.
Embryos are thawed, assessed for viability, and surgically transferred into prepared pseudopregnant recipient mothers. Litters are born 19-21 days following surgical transfer. Tissue is provided from 2-3-week-old pups for genotying and results are expected within a week. Blood for pathogen testing is collected, if necessary, from the mothers, when pups are weaned. Specific pathogen-free (SPF) pups are then transferred to the investigator.
Reconstitution of live mice from frozen sperm includes performing ICSI with oocyte donors of the appropriate strain, generating pseudo-pregnant recipient females, transferring fertilized embryos to these dams and monitoring pregnancy. SPF pups are then transferred to the investigator.