miR-182-flox mice possess loxP sites flanking the entire microRNA-182 coding region making this strain useful for studying tumor metastasis in the lungs.
David Kirsch, Duke University Medical Center
miR-182-flox mice possess loxP sites flanking the entire microRNA-182 coding region. miR-182 is a microRNA markedly overexpressed in some tumors that metastasize to the lungs. Mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have miR-182 deleted in the cre-expressing tissues.
These mice were bred to KP mice (mix of two other floxed mice: LSL-K-rasG12D (Stock No. 008179) and p53LoxP (Stock No. 008462)), and had an Ad-Cre vector injected into the muscle. No significant changes in tumor onset or tumor growth kinetics are seen after deletion of miR-182. Six months after surgical removal of primary tumors, mice exhibit a decrease in the rate of lung metastasis: from 43% in WT mice, to 20% and 13% in heterozygous or homozygous miR-182 KO mice, respectively.
When initially bred to KPY mice (KP with an additional LSL-YFP allele (Stock No. 006148)), mice lacking miR-182 show a decrease from 90% of KPY mice with circulating tumor cells to only 50% of miR-182 KO KPY mice with circulating tumor cells.
A targeting vector was designed by Dr David Kirsch (Duke University) to insert loxP sites flanking the microRNA-182 (MiR-182) coding region. A frt-flanked neomycin resistance (neo) cassette was placed within the floxed region. The construct was electroporated into 129Sv-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and resulting chimeric mice were bred with C57BL/6 females. Offspring were bred to 129S4/SvJae-Gt(ROSA)26Sortm2(FLP*)Sor/J transgenic mice (Stock No. 007844) to delete the neo cassette and progeny were crossed to remove the Flp-expressing transgene. The resulting miR-182-flox mice were maintained on a mixed background. Upon arrival, 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 1.1, David Kirsch|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Mir182, microRNA 182|
|Strain of Origin||129/Sv|
|Molecular Note||The targeting vector is designed to insert a loxP site upstream of the Mir182 coding region and a FRT-flanked neomycin resistance (neo) cassette downstream of the coding region followed by a second loxP site. Flp-mediated recombination removed the FRT-flanked neo cassette.|
When maintaining a live colony, homozygous mice may be bred together.
When using the Mir182f mouse strain in a publication, please cite the originating article(s) and include JAX stock #028610 in your Materials and Methods section.