Tmprss2-/- KO mice may be useful for studying the role of TMPRSS2 in influenza virus replication and pathogenesis, as well as prostate cancer.
Human cellular entry of coronaviruses, including severe acute respiratory syndrome coronavirus-1 (SARS-CoV) and -2 (SARS-CoV-2), is dependent on viral spike protein binding to the human ACE2 receptor and on spike protein priming by the serine protease TMPRSS2. As such, these mice may be useful for studying antiviral therapies to coronavirus and the disease outbreak COVID-19.
Peter S. Nelson, Fred Hutchinson Cancer Research Center
Tmprss2-/- knock-out mice contain a loxP-flanked neo cassette in place of exons 10-13 of the transmembrane protease, serine 2 (Tmprss2) gene, abolishing gene function. There is no evidence a protein product is generated from the alternatively-spliced transcript. TMPRSS2 is a membrane associated serine protease, expressed in the epithelium of the human respiratory tract and prostate glands. It has been shown to activate hemagglutinin proteins of human influenza viruses and is implicated in prostate carcinogenesis. Sequence analysis indicates the presence of a truncated Trmprss2 transcript due to splicing of exon 9 to exon 14. This transcript is present at a 20% reduction compared to the WT transcript, while there is an 80% reduction in the full length transcript compared to WT. The lungs of homozygous Tmprss2-/- mice are protected against viral spread, showing only very mild pathogenesis after infection with H1N1 virus. These mice also display reduced body weight loss and mortality after H3N2 infection but to a much lower degree than for H1N1 infected mice. They also show less severe pathogenesis after infection with H3N2 virus. Viral titers are decreased in these mice after infection with both viruses compared to WT mice. No abnormal prostate phenotype is evident.Homozygotes are viable and fertile.
A targeting vector was designed to replace exons 10-13, encoding the serine protease domain, of the transmembrane protease, serine 2 (Tmprss2) gene with a loxP-flanked neomycin resistance (neo) cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl+-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeric males were bred to C57BL/6J females. These mice were bred to C57BL/6J mice for at least 5 generations by the donating lab. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 1, Peter Nelson|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Tmprss2-; Tmprss2tm1Tsyk|
|Gene Symbol and Name||Tmprss2, transmembrane protease, serine 2|
|Strain of Origin||(129X1/SvJ x 129S1/Sv)F1-Kitl+|
|Molecular Note||A targeting vector was designed to replace exons 10-13 with a loxP-flanked neo. The deleted exons encode 2 of 3 catalytic residues essential for serine protease activity. Quantitative RT-PCR failed to detect transcript of exons 11 and 13. Mutants expressed only a 20% reduction in transcripts spanning exons 3 and 4 or 5 and 6, however, mutants expressed 80% less transcript of the 3' UTR than wild-type mice. Sequencing revealed that mutant transcripts alternatively splice exon 9 to exon 14.|
When maintaining a live colony, homozygous mice may be bred together.
When using the Tmprss2 knock-out mouse strain in a publication, please cite the originating article(s) and include JAX stock #026196 in your Materials and Methods section.