STOCK Dicer1^tm1Bdh/J

Stock number: 006001
Product name: Dicer-floxed
Research areas: Cell Biology Research, Research Tools

Description

These floxed mutant mice possess loxP sites flanking exon 23 of the Dicer1 gene. This strain may be useful for generating conditional mutations in applications related to embryonic development, translation, protein processing and miRNA/siRNA regulation of gene expression.

Detailed description

These mice contain loxP sites on either side of exon 23 of the targeted gene. Mice homozygous for this "Dicer-flox" allele are viable and fertile and exhibit no gross phenotypic or behavioral abnormalities. Expression of the targeted allele is indistinguishable from wildtype despite the presence of an frt-flanked neomycin cassette between exon 23 and the 3' loxP site. Cre-mediated recombination (resulting in deletion of exon 23) in the germline leads to developmental arrest at embryonic day 7.5 (E7.5). Tissue specific deletion results in the loss of microRNA (miRNA) processing. Mutant mice can be used to generate cell/tissue-specific deletions of the endogenous gene for applications in embryonic development, translation, protein processing and miRNA/siRNA regulation of gene expression.

For example, when crossed to a strain expressing Cre recombinase in mesenchyme (see Stock No. 005584), this mutant mouse strain may be useful in studies of limb morphogenesis.

When bred to a strain expressing Cre recombinase in the neural tube (see Stock No. 009107 for example), this mutant mouse strain may be useful in studies of DiGeorge syndrome, miRNA biogenesis and neural crest cell development.

When bred to a strain expressing Cre recombinase in the distal posterior region of E10-E12 embryos (see Stock No. 005622 for example), this mutant mouse strain may be useful in studies of lung epithelial morphogenesis.

When bred to a strain expressing Cre recombinase in Foxp3+ cells from the lymph nodes, spleen and thymus (see Stock No. 014579 for example), this mutant mouse strain may be useful in studies miRNA and the function of T reg cells.

When bred to a strain expressing Cre recombinase in Foxp3+ regulatory T cells (Foxp3^{tm4(YFP/cre)Ayr}; see Stock No. 016959 for example), this mutant mouse strain may be useful in studies inflammation and the function of T reg cells.

Development

A targeting vector was used to flank exon 23 (encoding most of the second RNaseIII domain) of the endogenous gene with loxP sites. The vector also contained an frt-flanked neomycin resistance cassette between the exon and downstream loxP site. This construct was electroporated into ?129? embryonic stem (ES) cells. Correctly targeted cells were injected into C57BL/6J blastocysts and chimeric mice were bred to C57BL/6J for germline transmission. Heterozygous offspring were bred to generate homozygotes. At some point, homozygotes were bred to mutant Gt(ROSA)26Sor mice on an unknown background. Upon arrival at The Jackson Laboratory, mutants will be bred to C57BL/6J mice and then wild-type siblings for multiple generations while selecting for the "Dicer-floxed" allele and against the mutant Gt(ROSA)26Sor allele. After this, mice containing only the "Dicer-floxed" allele will be bred together to create a homozygous colony.

Allele

Symbol: Dicer1^tm1Bdh
Name: targeted mutation 1, Brian D Harfe
MGI accession ID: MGI:3589208
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Dicer1
Marker name: dicer 1, ribonuclease type III
Chromosome: 12
Strain of origin: 129
Molecular note: A targeting vector was designed to insert loxP sites around the exon that encodes most of the second RNaseIII domain as well as an frt-flanked neo within the loxP-encompassed sequence. Cre-mediated removal of the sequence would result in the loss of 90 amino acids, a loss that does not create a downstream frame-shift or an unstable protein.