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Strain Information

Name: angiotensin I converting enzyme (peptidyl-dipeptidase A) 2; endonuclease-mediated mutation 1, Mouse Biology Program
Type: Allele
Species: Multi-species
Chromosome: X
Name: angiotensin I converting enzyme (peptidyl-dipeptidase A) 2
Synonyms: 2010305L05Rik
Type: Gene
Species: Mus musculus (mouse)
Chromosome: X
NCBI: 70008
Homologene: 41448
Genetic Alterations
Generation of a humanized ACE2 (ENSG00000130234.13) mouse line. Human DNA consisting of 5'UTR, CDS (exons 2-19) fused to mouse 3'UTR replaced the DNA region in mouse Ace2 gene stretching from the 5'UTR to the starting ATG in exon 2. The approach minimizes potential downstream splicing or RNP re-cleavage. CRISPR RNP was used to assist with homologous recombination using dsDNA repair in ES cells. The expression of the human CDS is controlled by the mouse regulatory systems (including 3’UTR) as the expression pattern is similar between species and especially high in the lungs.
ES Cell Line
JM8A3 derived from C57BL/6N

The humanized knock-in ACE2 (hACE2) mice express ACE2 at a level and pattern similar to Ace2 expression in wild type mice. In contrast, mouse Ace2 expression is 30-40 fold lower in the humanized knock-in ACE2 mouse in which the mouse allele was interrupted by the human coding sequence. To validate that hACE2 mice are susceptible to SARS-CoV-2, 9 male and 9 female 8-week-old mice were challenged intranasally with 105 plaque forming units (PFU) of a delta lineage strain of SARS-CoV-2 (B.1.617.2, hCoV-19/USA/PHC658/2021). The dose was pre-determined to be uniformly lethal in B6.Cg-Tg(K18-ACE2)2Prlmn/J (K18) mice which were used as positive controls (n=6). Mock inoculated hACE2 mice (n=7) treated with PBS served as negative controls. Mice were monitored daily for weight loss and disease signs for 10 days. Parallel patterns of transient weight decreases were observed on days 2-5 for all groups, with more pronounced weight loss in K18 mice which were all euthanized by day 6 due to greater than 20% loss of starting body weight. Weight loss was not limited to one biological sex and did not correlate with starting weight. Aside from transient weight loss, hACE2 mice showed no disease signs (ataxia, e.g.), contrasting with K18 mice which were severely lethargic on days 5 and 6. Infectious SARS-CoV-2 levels were assessed by testing tracheal swabs on days 1-6, and serum, lung, heart, kidney, and brain from a subset of mice euthanized on days 2, 4, and 6. Infectious SARS-CoV-2 was not detected in any serum, heart, or kidney sample from any mouse, but was detected in just 1 tracheal swab from a hACE2 mouse on day 1, which contrasted with SARS-CoV-2 detections from all K18 mice on day 1 and in most on day 2. SARS-CoV-2 levels in lungs of hACE2 and K18 mice were similar, with highest titers on day 2. Unlike in K18 mice, no hACE2 mouse contained detectable infectious virus in brain. Detection of SARS-CoV-2 RNA in tracheal swabs on at least 2 days from days 1-3 correlated with detection of infectious virus in lungs in both KI hACE2 and K18 mice. These results demonstrate that the proposed experimental conditions reproducibly cause non-lethal SARS-CoV-2 infection in hACE2 mice and that measuring SARS-CoV-2 RNA in tracheal swabs can be used as a minimally invasive approach to confirm infection.

Strain Development
CRISPR RNP was used to assist with homologous recombination using dsDNA repair template in JM8A3 ES cells derived from C57BL/6N. Following blastocyst injection, the chimeras were mated with C57BL/6NCrl to create germline heterozygotes. Long-range PCR products were fully sequenced; potential off-targets were absent. Subsequent backcross to C57BL/6NCrl.
Suggested Control Mice
C57BL/6NCrl or wild-type siblings
MMRRC Genetic QC Summary
The MMRRC Centers have developed a genetic QC pipeline using MiniMUGA array genotyping to provide additional information on strain backgrounds for MMRRC congenic and inbred strains. For more information on when data may be available, or to request genotyping for a strain of interest, please contact Older strains may not have this information.
  • Immunology and Inflammation
Kent Lloyd, D.V.M., University of California, Davis.
Primary Reference
Pending publication

Colony and Husbandry Information

Colony's Current Health Status Report

For more information about this colony's health status contact
Coat Color
Black or agouti
MMRRC Breeding System
Backcross and sib-mating
N2 (C57BL/6NCrl), F1
Overall Breeding Performance
NOTE: "Hemizygote" as used here refers to males carrying a mutation on the X Chromosome or mice of either sex carrying an inserted transgene with no homologous allele on the other chromosome.
Average litter size
7 to 9
Recommended wean age
3 Weeks
Average Pups Weaned
7 to 9

Order Request Information

Limited quantities of breeder mice (up to 2 males and 2 females or 4 mice) per investigator per month are available from a live colony, usually available to ship in under 12 weeks. Larger quantities may be available, please contact the distributing center directly at for more details.

Cryopreserved material may be available upon request, please inquire to for more information.

A license from third party patent owner(s) may be required for for-profit entities to use mouse models derived from CRISPR-Cas9 technologies and it is the Users sole responsibility to determine whether such a license is necessary.

Distribution of this strain requires submission of the MMRRC Conditions of Use (COU). A link to the COU web form will be provided via email after an order has been placed; the form should be completed then or the email forwarded to your institutional official for completion.

Additional charges may apply for any special requests. Shipping costs are in addition to the basic distribution/resuscitation fees. Information on shipping costs and any additional charges will be provided by the supplying MMRRC facility.

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MMRRC Item # Description Distribution Fee / Unit (US $)
*Shipping & Handling not included*
Units Notes
Homozygous Female
Heterozygous / Hemizygous Female
Heterozygous / Hemizygous Male
Wild Type Female
Wild Type Male
$272.50 / $674.71
Non-Profit / For-Profit
Per Mouse The may assess additional fees for any special requests (e.g., specific age or weight of mice, etc.).
available service Rederivation to a Barrier Facility $2,800.00 / $6,003.46
Non-Profit / For-Profit
Per Mouse These mice were derived as part of a supplement project for generation of COVID models at the Mouse Biology Program (MBP) at UC Davis. To ensure rapid availability they are being offered as live mice from the MBP production facility, which is not within the M3 Barrier Facility that the MMRRC at UC Davis normally distributes from. Therefore if your institution has approved MMRRC at UC Davis as a vendor, we recommend selecting Rederivation to a Barrier Facility, or discussing this with your animal health coordinator prior to placing the order 1
068346-UCD-SPERM Cryo-preserved spermatozoa $546.25 / $869.88
Non-Profit / For-Profit
Aliquot Approximate quantity3
Cryopreserved material may be available upon request, please inquire to for more information.

1 The distribution fee covers the expense of rederiving mice from a live mouse; you will receive the resulting litter. The litter will contain at minimum one mutant carrier; the actual number of animals and the gender and genotype ratios will vary. (Typically, multiple breeder pairs can be established from the recovered litter.) Prior to shipment, the MMRRC will provide information about the animals recovered. If you anticipate or find that you need to request specific genotypes, genders or quantities of mice in excess of what is likely from a resuscitated litter, you may discuss available options and pricing with the supplying MMRRC facility.

3 An aliquot is one straw or vial with sufficient sperm to recover at least one litter of mice, as per provided protocols, when performed at the MMRRC facility. The MMRRC makes no guarantee concerning the success of these procedures when performed outside the MMRRC facilities.

To request material from the MMRRC: Please fill out our on-line request form (accessible from the catalog search results page, or click the Request this Strain button in the fees section). If you have questions or need assistance completing this form, you may call Customer Service at (800) 910-2291 (in USA or Canada) or (530) 757-5710 (international calls). Before you call, please have with you: the MMRRC item number, quantity needed, Bill-to and Ship-to contact information.