CRYOPRESERVATION OF TRANSGENIC MOUSE EMBRYOS BY ULTRARAPID FREEZING

Two transgenic mice lines were produced by introducing the rat GH anti sense transgene and the chicken beta-actin promoter/firefly luciferase hybrid gene in our labolatory. We cryopreserved the transgenic embryo s, obtained by fertilization in vitro with the sperm of hemizygous mal es for the transgene, by the ultrarapid freezing. The survival rates o f cryopreserved 2-cell embryos were high (>70%) at thawing in both lin es and 53% and 16% of cryopreserved 2-cell embryos, respectively, deve loped to live young after transferring to oviducts of recipients. Each transgene was detected at about 40% of the live young from two transg enic lines. These results indicated that the cryopreservation of embry os by ultrarapid freezing was valuable for sustaining transgenic mouse lines without genetic contaminations.