The mice to be rederived--a minimum of 3 (maximum of 10) fertile, carrier
males and the purchase of females to superovulate.
What We Will Provide
A detailed schedule proposal with specific instructions regarding the
purchase of donor females and preparation of males
Hormones, hormone injection and mating of the mice to be rederived.
Pseudopregnant recipient females.
Transfer of the embryos to recipients. Our goal is to provide you with sufficient rederived mice to reestablish the strain. To reestablish your strain, keep in mind that we must use wild type donor females for rederivation.
CWRU clients will receive the recipient mother(s) and their offspring a few days after birth. Clients outside of CWRU will receive weaned offspring.
Investigators need an IACUC protocol from their institution to receive mice from the core. CWRU IACUC protocols need to specify use of the Case Transgenic Core.
$2,000. An additional minimum of $200 for animal packing/transport will be charged for non-CWRU local orders.
No charge for a failed first attempt if client fulfills their contract responsibilities.
Full charge for cancellations after approval of schedule proposal.
From the start of rederivation, it will be about 4 weeks before we will be able to deliver mice to you.
Currently (1/23/22), the time between order placement and the start of rederivation is 3 weeks.
You will need the following information to order
PI name, address and contact info
IACUC protocol number
Age of males
Number of males
Current location of mice
Location to deliver clean mice to
Success Rates in Rederivation
The core generates an average of about 16 pups per rederived strain.
Frequently Asked Questions
What is rederivation?
Rederivation is used to establish Specific
Pathogen Free (SPF) mice. We transfer preimplantation embryos into SPF
pseudopregnant recipient females. This procedure is more reliable than
caesarian delivery for removal of pathogens.
Which pathogens will remain?
The mice that we provide are as clean as mice
from The Jackson Laboratory and Charles River. Our mice are Specific Pathogen-Free, and are negative for Helicobacter sp and Norovirus. If you have concerns about other pathogens and commensals, please discuss your concerns with us prior to attempting rederivation. You should be aware that most animal housing rooms at CWRU are positive for Helicobacter sp and Norovirus. If you wish to exclude these pathogens from mice you obtain from us, you will need to coordinate your rederivation efforts with the ARC management to find appropriate housing.
Which strains of mice?
All strains of mice can be rederived, but
the efficiency of the procedure depends on the robustness and fecundity
of the strain. Inbred strains require larger starting numbers of mice
for a reasonable chance of success.
How many mice of each sex?
Robust strains: three superovulated, plugged
females. Inbred strains: five or more superovulated, plugged females.
To obtain these numbers, you will need a comparable number of individually
housed stud males, and a slightly greater number of females (assume a
plug rate of 75%).
What can be done to ensure success?
The stud males must be older than 2 months
of age, and less than a year old. The stud males should be experienced at mating, but rested before attempting rederivation.
Use your males, and purchase wild type females of the appropriate strain to obtain enough young, sexually mature females. Consult with us on numbers.
What is superovulation?
Superovulation is the forcing of the estrus cycle through timed injection of hormones, allowing us to synchronize and schedule matings. Superovulation also can lead to greater numbers of eggs in some strains.