These floxed mutant mice possess loxP sites flanking Mirc21 (mir-34b/c). This strain may be useful for generating conditional mutations in applications related to somatic cell reprogramming, stem cell differentiation, spermatogenesis, neuronal development, aging, and tumor suppression.
Lin He, UC-Berkeley
The mir-34 microRNA precursor family has 3 members: Mir34a, Mir34b and Mir34c, which all share the same seed sequence. As Mir34b & Mir34c share a primary transcript, they are known as Mirc21, microRNA cluster 21, including Mir34c through Mir34b. All 3 mir-34 members are transcriptional targets of p53.
These mice possess loxP sites on either side of the targeted Mirc21 microRNA cluster and 200bp of flanking sequence. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have the Mirc21 microRNA cluster (and the FRT flanked NEO cassette) deleted in the cre-expressing tissues.
When bred to a strain with widespread Cre recombinase expression, this mutant mouse strain may be useful in studies of somatic cell reprogramming.
A targeting vector containing a FRT site flanked NEO cassette with a downstream loxP site, was inserted downstream of Mirc21. A second loxP site was inserted upstream of Mirc21. The construct was electroporated into (C57BL/6 x 129S4/SvJae)F1 derived v6.5 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts.
The resulting chimeric animals were tested for germline transmission. The mice were crossed to FLP recombinase expressing mice on a congenic C57BL/6 background (see Stock No. 005703) to remove the FRT flanked NEO cassette.
The mice were then backcrossed to C57BL/6 for at least 6 generations. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
|Allele Name||targeted mutation 1.2, Lin He|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Mirc21, microRNA cluster 21, including Mir34c through Mir34b|
|Strain of Origin||(C57BL/6 x 129S4/SvJae)F1|
|Molecular Note||A loxP site was inserted upstream of Mir34b and an FRT-flanked neo cassette with a 3' loxP site was inserted downstream of Mir34c. Flp-mediated recombination removed the FRT-flanked neo cassette.|
When maintaining a live colony, these mice can be bred as homozygotes.
When using the mir-34b/cflNeo mouse strain in a publication, please cite the originating article(s) and include JAX stock #026010 in your Materials and Methods section.