Mfn1loxP mice floxed mice may be useful for generating conditional mutations in applications related to the study of mitochondrial fusion and morphology.
David C Chan, California Institute of Technology
Mfn1loxP floxed mice possess loxP sites flanking exon 4 of the mitofusin 1 (Mfn1) gene. Mitofusin 1 encodes a transmembrane GTPase which mediates mitochondrial fusion. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre in a wide-spread manner, embryos die mid-gestation due to placental defects. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exon 4 deleted in the cre-expressing tissues.
A targeting vector was designed to insert a frt-flanked neomycin resistance (neo) cassette followed by a loxP site upstream of exon 4, and a second loxP site downstream of exon 4 of the mitofusin 1 (Mfn1) gene. The construct was electroporated into 129 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and resulting chimeric mice were bred to Black Swiss mice. Offspring were bred with Gt(ROSA)26Sortm1(FLP1)Dym transgenic mice on a 129 background to delete the neo cassette, and progeny were crossed to remove the Flp-expressing transgene. Mfn1loxP mice were further backcrossed to C57BL/6J mice (Stock No. 000664) for at least 10 generations. Upon arrival at the Jackson Laboratory, mice were bred to C57BL/6J inbred mice for at least one generation to establish the colony.
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 rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 3 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.
|Allele Name||targeted mutation 2, David C Chan|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Mfn1, mitofusin 1|
|Strain of Origin||129|
|Molecular Note||FRT-flanked neo cassette followed by two loxP sites flanking the exon 4 encoding the canonical G-1 GTPase motif replaced the endogenous locus. The neo cassette was removed by crossing with FLP recombinase expressing mice.|
When maintaining a live colony, homozygous mice may be bred together.
When using the B6.129(Cg)-Mfn1tm2Dcc/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #026401 in your Materials and Methods section.