B6N.Cg-Dgcr8^tm1.1Blel/Mmjax

Stock number: 012562
Product name: Dgcr^2lox
Research areas: Cell Biology Research, Neurobiology Research, Research Tools

Description

These floxed mutant mice harbor loxP sites flanking exon 3 of the DiGeorge syndrome critical region gene 8 (Dgcr8) gene and may be useful in generating conditional mutations for studying the role of Dgcr8 in microRNA regulation.

Detailed description

Mice homozygous for this Dgcr8^2lox (or Dgcr8^flox) conditional allele are viable and fertile, with loxP sites flanking exon 3 of the Dgcr8 (DiGeorge syndrome critical region gene 8) locus. When bred to mice that express Cre recombinase, the resulting offspring will have the floxed region deleted in cre-expressing tissues. Such a deletion of exon 3 generates a frameshift mutation with multiple downstream premature stop codons resulting in a truncated protein missing the WW protein-protein interaction and RNA-binding domains. This deletion will disrupt Drosha/Dgcr8-dependent cleavage of precursor miRNAs in the nucleus and thus inhibit canonical microRNA biogenesis.

Development

A targeting construct was designed to insert a loxP site upstream of exon 3, and a loxP-flanked CMV-HygroTK selection cassette downstream of exon 3 of the Dgcr8 (DiGeorge syndrome critical region gene 8) locus. This construct was electroporated into (C57BL/6 x 129S4Sv/Jae)-derived V6.5 embryonic stem (ES) cells. Correctly targeted ES cells were then transiently transfected with a Cre recombinase-expressing plasmid. The resulting ES cells with the Dgcr8^2lox (Dgcr8^flox) genotype (CMV-HygroTK selection cassette removed; leaving a single loxP site upstream of exon 3 and a single loxP site downstream of exon 3) were injected into recipient blastocysts. Chimeric mice were bred with C57BL/6NCr inbred mice to generate the Dgcr8^2lox colony. Mutant mice were backcrossed to C57BL/6NCr for eight generations, and thereafter maintained by breeding homozygous mice together for many generations prior to sending to the MMRRC at The Jackson Laboratory Repository. Upon arrival, mice were bred with C57BL/6NJ inbred mice for at least one generation to establish the colony.

Allele

Symbol: Dgcr8^tm1.1Blel
Name: targeted mutation 1.1, Robert Blelloch
MGI accession ID: MGI:4458072
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Dgcr8
Marker name: DGCR8, microprocessor complex subunit
Chromosome: 16
Strain of origin: (C57BL/6 x 129S4/SvJae)F1
Molecular note: A loxP site was inserted in intron 2 and a floxed CMV-Hygro selection cassette was inserted in intron 3. ES cells were sequentially targeted so that ES cells carried two mutated alleles. Cre recombinase treatment of these ES cells resulted in two mutant alleles, this one with a floxed exon 3 but lacking the selection cassette and another allele which lacks both exon 3 and the selection cassette.