B6.129-Nos1^tm1(cre)Mgmj/J

Stock number: 017526
Product name: Nos1^cre
Research areas: Neurobiology Research

Description

These Nos1^cre knock-in mice may be useful for generating conditional mutations for studying metabolism and energy homeostasis.

Detailed description

This Nos1^cre strain expresses Cre recombinase from the endogenous Nos1, neuronal nitric oxide synthase 1, locus. Mice that are heterozygous or homozygous for the targeted mutation are viable and fertile. NOS1-expressing tissues typically include discrete populations of neurons in the cerebellum, olfactory, bulb, hippocampus, cortex, striatum, basal forebrain and brain stem. Users should be cautioned that periodic expression during gametogenesis is also observed (see below). When crossed with a strain containing a loxP site-flanked sequence, Cre-mediated recombination results in tissue-specific deletion of the sequence in the offspring.

Luo et al. 2020 Neuron 106:37 Table 1 shows germline recombination in offspring (F2) of Cre;floxed double mutant (F1) mice bred to floxed and/or wildtype mice. The authors also note that in general, the frequency of recombination in Cre;floxed double mutant germline cells appears to be considerably higher than in zygotes produced by breeding Cre mice to floxed mice.
This reports that Nos1^cre;floxed double mutant females bred to floxed males produced some offspring with germline deletion of the floxed allele. Cre expression in the male germline was not determined. As such, for Cre-lox experiments and to avoid/minimize germline deletion of the floxed allele, researchers may consider breeding Nos1^cre males to floxed females.
If the recombinase activity pattern of this allele is further characterized by the Genetic Resource Science group at The Jackson Laboratory, such findings will be reported on the Mouse Genome Informatics (MGI) Allele Detail entry. This same information may also be found searching the MGI Recombinase Activity and MGI Gene Expression + Recombinase Activity Comparison Matrix.

Development

IRES and cre recombinase sequence was inserted in the 3' UTR of the Nos1 gene. The construct was electroporated into 129 derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice, and then backcrossed to C57BL/6J for 9 generations. These mice contain a FRT-flanked NEO downstream of the Nos1 gene. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

Allele

Symbol: Nos1^tm1(cre)Mgmj
Name: targeted mutation 1, Martin G Myers, Jr
MGI accession ID: MGI:5301174
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Nos1
Marker name: nitric oxide synthase 1, neuronal
Chromosome: 5
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Includes discrete populations of neurons in the cerebellum, olfactory, bulb, hippocampus, cortex, striatum, basal fore-brain and brain stem. Periodic expression during gametogenesis is also observed in gametes.
Molecular note: An IRES-cre-Frt-neo-Frt cassette was inserted after the stop codon of the final 3' exon of the Nos1 gene by homologous recombination in R1 ES cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice, and then backcrossed to C57BL/6J for 9 generations.