These mice may be useful when studying CD73-generated adenosine receptor signaling and antitumor immune responses.
Linda F. Thompson, Oklahoma Medical Research Foundation
A neo cassette replaces exon 3 of the ecto-5' nucleotidase (Nt5e) gene, abolishing CD73 enzyme activity. A shorter transcript is produced at about 10% of WT levels, but no functional protein is detectable. Nt5e encodes Cd73, a membrane-bound glycoprotein expressed on many cell types including subsets of T and B lymphocytes including regulator T cell (Tregs), endothelial cells, and mesenchymal cells. CD73 can hydrolyze nucleoside monophosphates, such as AMP, into bioactive intermediates like adenosine. CD73-generated adenosine activates transmembrane adenosine receptors and can act as either a pro- or anti-inflammatory mediator. Adenosine also regulates endothelial permeability, platelet activation, leukocyte adhesion, and lymphocyte migration into draining lymph nodes after an inflammatory stimulus. CD73-dependent adenosine receptor signaling protects mice during renal ischemia and inhibits vascular leakage during hypoxia. CD73 inhibits antitumor immune responses and is tolerogenic for cardiac and airway allografts. Homozygous CD73-/- mice are viable and fertile. Under hypoxic conditions, these CD73-deficient mice exhibit increased vascular leakage and display increased edema in all organs except the brain. CD73 deficient mice are protected from experimental autoimmune encephalomyelitis (EAE). The severity of graft-vs-host disease (GVHD) is increased in these mice, as are anti-tumor immune responses.
A targeting vector was designed to replace exon 3 of the ecto-5' nucleotidase, (Nt5e) gene with a neomycin resistance (neo) cassette in reverse orientation to the gene. The construct was electroporated into 129S1/Sv-Oca2+ Tyr+ Kitl+-derived CJ7 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric female was bred to a C57BL/6J male. The resulting heterozygous mice were crossed and their homozygous offspring were backcrossed to C57BL/6J mice for at least 14 generations (see SNP results below) prior to sending males to The Jackson Laboratory Repository in 2012. Upon arrival, males were used to cryopreserve sperm. To establish the living mouse colony, an aliquot of the frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
In 2013, a 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the first generation rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 3 of the 5 markers that determine C57BL/6J from C57BL/6N were found to be heterozygous in all mice tested. These data show that the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N and C57BL/6J genetic background.
Subsequent SNP testing was performed yearly from 2017-2020 on cohorts from the live colony using a 48 SNP panel, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains. The 43 markers throughout the genome all show C57BL/6 genetic background, and the C57BL/6 substrain markers all show homozygous C57BL/6J.
|Allele Name||targeted mutation 1, Linda F Thompson|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Cd73-; CD73-KO|
|Gene Symbol and Name||Nt5e, 5' nucleotidase, ecto|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|Molecular Note||Exon 3 was replaced with a neo cassette in reverse orientation to transcription. Northern blot of kidneys from mutant animlas indicated a lack of transcript.|
|Mutations Made By|| |
Linda Thompson, Oklahoma Medical Research Foundation
When maintaining a live colony, homozygous mice may be bred together.
When using the Cd73- mouse strain in a publication, please cite the originating article(s) and include JAX stock #018986 in your Materials and Methods section.