Central Transgenic Core

In Vitro Fertilisation (IVF)

Information about the use of IVF using fresh or frozen sperm to rederive existing transgenic lines

Technician performing in vitro fertilisation

When is IVF used?

  • Shipment of frozen sperm: This is one of the standard options for redistribution of rodent lines around the world. It is cost-effective and eliminates animal welfare issues with transportation of live mice. For further information about importing frozen sperm, please see our Importation page.
  • Rederiving a previously in-house cryopreserved line: Instead of continous breeding of a line it can be more cost-effective and in line with the 3Rs to cryopreserve sperm in-house followed by IVF-mediated rederivation if the line is needed again in the future.
  • Moving a line: If a researcher wants to move a line between BVS facilities with diverging health status, IVF using fresh or frozen sperm can be used.
  • In vitro CRE-mediated deletion: During IVF, incubation of the fertilised embryos with TAT-CRE allows for efficient deletion of a floxed fragment (e.g. selection cassette, conversion of a conditional into a conventional KO).
  • Rescuing a line: IVF can also be used to rescue a line that has been reduced to one or two males.
  • Rapid amplification of large animal numbers: If large numbers of experimental animals are required in a single cohort, IVF may be more cost-effective than standard breeding.

 

Fresh or frozen sperm?

Even the best freezing procedure will unavoidably affect sperm mobility and quality. Therefore, if available, fresh sperm is preferrable. Fresh sperm can be sent within the cauda epididymis at refrigerated temperatures (4-8°C) whilst maintaining its fertility for at least 72 hours. This allows low-cost transport of samples not only within Edinburgh, but also within Europe.

 

Researcher’s responsibilities during process:

  • Complete the ‘Request to Produce Transgenics Form’ (see below) and return it to the CTC manager.

 

CTC’s responsibilities during process:

  • CTC will organise the purchase and superovulation of female wild type donor and recipient mice (CD1) on behalf of the researcher.
  • CTC will organise the genotyping of rederived animals through Transnetyx, and also carry out genetic monitoring using Transnetyx' MiniMUGA assay for 2 animals with correct genotype.
  • If live animals are used for sperm collection, CTC will coordinate the rederivation with the respective BVS unit manager.