Mouse Colony Expansion


General Description


The goal of this service is to provide investigators with age-matched GEM models for their experiments. The complexity of current GEM models requires the maintenance of large breeding colonies and considerable time to acquire the appropriate number of mice for experiments. The GERM Core will utilize superovulation and embryo transfer to provide Investigators with the required numbers of mice of specific genotypes necessary for their experiments.

What Will Happen

  1. Investigator will submit a request form through iLabs, filling out detail information on male and female mouse numbers and ages. An account and IACUC number must be provided at this time. The Investigator IACUC protocol must be approved for all procedures performed in the Investigator laboratory.
  2. The core will review investigator-provided information and approve the request. The core will schedule the colony expansion according to the female mouse age and coordinate with the investigator.
  3. Investigators will complete the following steps to prepare embryos:
    • a. Investigator will prepare 8-10 adult males and 8-10 young female mice at age of 3-5 weeks with appropriate genotypes.
    • b. One week before the scheduled service date, pick up 1 tube of M2 media, 1 tube of PMSG, and 1 tube of HCG from the GERM Core. Note: Bring an ice bucket to put the hormones in and put them in a -20C freezer when you get back to your lab. Dilute the hormones right before you go to give the injections.
    • c. PMSG is administered via intraperitoneal injection (IP), at 10 a.m. three days before the scheduled rederivation date (e.g. Tuesday for rederivation on Friday). Dilute the PMSG with 950 ul of 0.9% saline and administer 0.1cc IP per mouse.
    • d. HCG is administered via IP injection 47 hours after PMSG, at 9 a.m. one day before the scheduled rederivation date (e.g. Thursday for procedure on Friday). Dilute the HCG with 950 ul of 0.9% saline and administer 0.1cc IP per mouse.
    • e. Place the females with the males immediately after administering HCG.
    • f. The morning following the HCG injections, the females are removed from the male cages and oviducts are collected into M2 media provided by the GERM Core.
    • g. Label the tubes with the iLab request number. Deliver the oviducts to ABBR R119A and leave in the biosafety hood at room temperature no later than 9 a.m.
  4. The core will dissect, digest, and collect all oocytes from the oviducts, identify and transfer fertilized 1-cell embryos to pseudo pregnant ICR females to allow gestation.
  5. Live-born founder animals will be held by the GERM Core until 10-14 days of age and subsequently transferred to the Investigator.

What is Expected

  1. The GERM core will transfer about 150 embryos if available to 10 of 0.5-day pseudo pregnant recipient mice.
  2. With good superovulation, it is expected that the Investigator will likely receive30-40 mice for experimental purposes.
  3. If there are no fertilized embryos collected, the core will charge 40% of cost. Investigators can repeat the colony expansion at 100% cost.