Cryopreservation

On this webpage  you can find a  submission form, which you should complete and send to EMMA via the website. On the submission form you will be asked to give information on depositor and owner, mutation(s), phenotype, genetic background and sanitary status of your mouse/rat strains, literature references, scientific interest and intellectual property rights, as well as some additional information that is needed for handling the animals. Upon sending your submission you will receive an automatic email notification. Applications for archiving are evaluated by an external Evaluation Committee and, if the information provided through the submission form is clear enough, EMMA will contact you within 60 days and discuss how to proceed. Do not hesitate to contact  VASENSEBAGVRE if there are questions you would like to address in advance.

Anybody who wants his/her mutant strains cryopreserved may deposit strains with EMMA. However, depositors must be aware that these strains become freely available to other researchers following deposition in EMMA.

Once approval has been granted, the archiving EMMA node will inform the submitter about which documents are required and which animals (age, sex, numbers) need to be provided. For example, depositors have to provide a health status report for the animals they want to send to EMMA. This report must be less than 3 months old.

In the case of mouse lines, due to its methodological simplicity and reduced costs, for most strains sperm will be cryopreserved. Depositors are then asked to send a minimum of 5 heterozygous or homozygous males (as appropriate) of breeding age to the EMMA node to which the mouse line has been assigned to for cryopreservation. If a strain needs to be frozen down at homozygous state, embryos will be cryopreserved and a minimum of 5 males and 5 females is required. Provision of more animals than the specified minimum will accelerate the freezing process. Under normal circumstances it will take EMMA between 4 and 6 months to freeze down a heterozygous mutant strain once the archiving centre has received the animals. This time frame includes a viability control.

The depositor has to bear the expense of shipping the mice to the EMMA partner responsible for archiving the strain. However, EMMA does not charge the depositor for the archiving service.

Major evaluation criteria are: sound scientific methods, evidence of heritability, identifiable genotype, and stabilised phenotype.

Please report in this field all details of all stages of the strain’s development and breeding history, also including:

1. The complete background of the strain on which the original mutation was produced/ original transgene construct was inserted. This would include but not limited to the following if/as applicable:

a. For Targeted Mutations (TM) or Endonuclease Mediated (EM) mutations – the complete background of targeted ES cell line/ injected blastocysts/ CRISPR/Cas-injected zygotes.
b. For Chemically Induced mutations (IN)- the complete background of treated animals and the used mutagen (e.g. ENU).
c. For Transgenic mice (TG)- the complete background of transgene-injected zygotes.
d. For Spontaneous mutations (SP)-the complete background of the strain on which the original spontaneous mutation arose.

2. The complete background of all the wildtype strains which the original mutant line was crossed with. Please include whether backcrossed or outcrossed and the number of crosses (generations).

3. The number of intercrossing generations (sister x brother mating), if/as applicable.

4. If the strain has been crossed with a Cre/Flp/Dre recombinase-deleter or a tissue/stage specific-driver strain, please include the published background along with relevant bibliography references for these strains.

Note: If possible, please include the substrains (For example : C57BL/6J instead of C57 or C57BL/6).

This information will be shown on the public strain list.

Several factors such as the mode of cryopreservation (sperm or embryo freezing), the genetic background and the health status of the mutant strain imported to EMMA influence the time required before a strain becomes available for distribution. Usually, we need 4 to 6 months to archive heterozygous mutant strains. Up to 12 months could be required for freezing a homozygous strain. The timelines include rederivation controls.

EMMA can grant a grace period of up to two years. During this grace period the mutant strain will be archived by EMMA but will not be published on the list of available EMMA strains. If you wish to make use of the grace period, you should complete the respective fields in the submission form and briefly explain why you need it.

Depositors can provide EMMA with a Material Transfer Agreement (MTA). If distribution requires a MTA, EMMA will not ship the strain until the recipient has signed the MTA. The MTA applies in relation between provider (depositor) and recipient. EMMA merely acts as a broker.

EMMA provides a nomenclature service for archived mice according to the rules and guidelines established by the International Committee on Standardized Genetic Nomenclature for Mice. Depositors should be aware that to aid curation of archived strains, official nomenclature (including laboratory code) will be requested from Mouse Genome Informatics (MGI) when required. All registered alleles etc. will remain reserved, but not public on the MGI website, until they appear in any publication, or the strain is made public on the INFRAFRONTIER website.

All EMMA partners use validated protocols for mouse embryo and spermatozoa freezing techniques, in vitro fertilisation procedures and embryo transfers. However, the EMMA partners use different protocols that are optimized for their individual settings. EMMA distribution centres will provide to users ordering frozen embryos or spermatozoa the centre specific validated thawing protocols. Your can download the protocols that are practiced in EMMA training courses at the MRC-Harwell and that are routinely used at Harwell.

Although publication is not a requisite for cryopreserving a strain at EMMA, it is highly appreciated that some phenotypic information is available. If the strain has been published, please add all publications where the submitted strain has been used in the ‘References’ section in the submission form. This information is useful for the evaluation of your submission, but also for users interested in obtaining your strain from EMMA in the future.
However, according to the EMMA policies, CRISPR strains can only be considered for archiving at EMMA if peer-reviewed phenotypic information is available.