STOCK Pnmt^{tm1.1(cre)Sne}/J

Stock number: 039729
Product name: Pnmt-Cre
Strain synonyms: B6J.129(Cg)-Pnmt^{tm1.1(cre)Sne}/J
Research areas: Cardiovascular Research, Endocrine Deficiency Research, Neurobiology Research, Research Tools

Description

Pnmt-Cre knock-in/knock-out mice have a cre-recombinase gene inserted into exon 1 of the Pnmt locus, abolishing endogenous Pnmt expression. When these mice are bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in the deletion of the floxed sequences in the Pnmt-expressing cells of the offspring. These mice may be useful when studying epinephrine (EPI) deficiency.

Detailed description

In the adrenal gland, norepinephrine is catalyzed into epinephrine by the enzyme phenylethanolamine N-methyltransferase (PNMT). Epinephrine plays a crucial role in stress response pathways, which include regulation of blood pressure and respiration. These Pnmt-Cre knock-in/knock-out (KI/KO) mice express a cre-recombinase under direction of the mouse Pnmt promoter, while also abolishing endogenous Pnmt expression.

Homozygous mice are viable and fertile with no overt phenotype; however, epinephrine is not detectable in adrenal tissue extracts from Pnmt-Cre KI/KO homozygotes. The donating laboratory confirmed recombination efficiency by crossing these Pnmt-Cre KI/KO mice to a R26R (LacZ) reporter mouse model (Stock No. 003474). LacZ expression is detectable in the heart, and neural folds of the midbrain-hindbrain junction. In adult adrenal tissues, LacZ expression is confined to Pnmt-expressing adrenergic cells. When these Pnmt-Cre KI/KO mice are bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in deletion of the floxed sequences in the Pnmt-expressing cells of the offspring. These mice may be useful when studying epinephrine (EPI) deficiency.

Development

This Pnmt-Cre knock-in/knock-out (KI/KO) strain was created in the laboratory of Dr. Karl Pfeifer at the NICHD/NIH in Bethesda, MD. The Pnmt-Cre (KI/KO) targeting vector was designed to insert a cre-recombinase into exon 1 of the phenylethanolamine-N-methyltransferase (Pnmt) gene. This construct also included an FRT-flanked neomycin cassette. The targeting construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-dervied R1 embryonic stem (ES) cells and correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric mice were bred with C57BL/6J mice (Stock No. 000664) to confirm germline transmission. Pnmt-Cre were then crossed to a Flp recombinase expressing mouse line to remove the neo cassette. The donating laboratory reorted that the mice were subsequently backcrossed to C57BL/6J mice for at least 5 generations prior to sending one male to The Jackson Laboratory in 2024 (see SNP note below). 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.

In 2024, a 48 SNP (single nucleotide polymorphism) panel analysis, 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, was performed on the male sent to The Jackson Laboratory Repository. Six of the 43 markers throughout the genome were segregating with 129. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed genetic background.

Allele

Symbol: Pnmt^{tm1.1(cre)Sne}
Name: targeted mutation 1.1, Steven N Ebert
MGI accession ID: MGI:7709523
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Pnmt
Marker name: phenylethanolamine-N-methyltransferase
Marker synonyms: Pent; PNMTase
Chromosome: 11
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Cre recombinase and an FRT flanked neomycin resistance gene were inserted into exon 1, creating an in-frame fusion gene. The FRT flanked neo from the allele Pnmt^tm1(cre)Sne was removed by a Flp recombinase.