Major Cryopreservation Effort for Mutant Mouse Stocks (November 1998)

The Mammalian Genetics Section of ORNL’s Life Sciences Division has launched a major cryopreservation effort for mutant mouse stocks. By freezing sperm and/or embryos, we propose to become a major archiving and distribution center for experimentally induced mouse mutations that have significant phenotypes of interest to the functional genomics and wider biological communities. Sperm freezing will provide a facile means for distributing any mouse mutation that is not male-lethal or male-sterile to the scientific community, and thawed embryos can very reliably be used to reconstitute many stocks, especially inbred strains, via transfer into recipient females.

Cryopreservation will also provide a logistically feasible means for rederiving the conventional (not pathogen-free) ORNL colony into a new, specific-pathogen-free (SPF) facility, when that facility becomes available within three years. We are endeavoring to freeze down mutant stocks now so that only those stocks that will be actively used upon opening of the new facility need be reconstituted. In the interim before our move into the clean facility, we will cryopreserve many stocks not used in active investigations in order to free our genetics staff for new experimental work.

In the last six weeks, since our effort has been running five to seven days a week, we have frozen 3000 embryos; this is more than were frozen in the entire previous year. We have also frozen sperm from 39 mutant stocks, and are collecting mice from an additional 80 stocks into the freezing queue. The effort over the last six weeks has included the quality-control measures necessary to ensure that our recovered embryos are fully viable and our thawed sperm competent for fertilization either by artificial insemination or in vitro fertilization. Staff members primarily responsible for these outstanding achievements are Sarah Shinpock, Kay Houser, and Debra Carpenter. We are also in active collaboration to test the efficacy of freezing whole ovaries for subdivision and transplantation into recipient females; this method would be invaluable for male-sterile and female-subfertile stocks. This collaboration includes testing to determine if embryos, sperm, and ovaries from non-SPF stocks still transmit any potential pathogens when used to reconstitute live stocks. (Contact: Dabney Johnson, dkj@ornl.gov, 423-574-0953; Funding Source: KP)