Embryo Cryo-preservation – University of Copenhagen

Core Facility for Transgenic Mice > Services > Embryo Cryo-preservation

Embryo Cryo-preservation

Embryo freezing is the most efficient way to cryo-preserve a mouse line, as it ensures the conservation of an identical genetic background and genotype after an eventual embryo thawing in order to resuscitate the line. It is specially indicated when it is needed to preserve a genetically modified mouse line which carries various mutations in different alleles.

Embryo Cryo-preservationYou would normally provide us with 5 to 10 young (2 to 6 moth old) healthy males that have been previously proved to be fertile. We would cross them with super-ovulated females in order to obtain a higher number of embryos. By default, we use C57Bl/6N females, but other genetic backgrounds can be considered upon request. We can also cross your mutant females with wild type males, or set up crosses between males and females from the same modified mouse line or, eventually, between individuals from different mutant lines.

Various rounds of crossing will be performed until a minimum of 200 (when the progenitors carry the mutation of interest in homozygosity) or 400 (when they are heterozygous) 2-cell embryos are collected and cryo-preserved by standard slow-freezing method. The frozen specimens are maintained in the liquid nitrogen tanks of the transgenic mouse facility.

At least one test of the quality of the preserved embryos will be performed by thawing and culturing a number of them. After culture alive embryos will be transferred to pseudopregnant recipient females. When alive pups have been generated from these transfers the service can be considered concluded.

If you would like to request this service, please fill out and send us the requisition form.

Please do not hesitate to contact us if you have any questions regarding this technique or the form.