B6.Cg-Snord116^tm1Uta/J

Stock number: 008118
Product name: 2-loxp (floxed)
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

As deletions of the Snord116 cluster are associated with Prader-Willi syndrome (PWS), mice carrying the 2-loxP (floxed) allele may be useful in generating conditional mutations for studying the role of Snord116 in growth and feeding regulation, mechanisms of obesity, and pathophysiology of Prader-Willi syndrome. Of note, mice harboring a deletion of the Snord116 cluster are also available (see Stock No. 008149).

Detailed description

Mice homozygous for this 2-loxP (floxed) allele are viable and fertile, with loxP sites flanking the Snord116 small nucleolar RNAs (snoRNAs) gene cluster. When bred to mice that express Cre recombinase, the resulting offspring will have this gene cluster deleted in the cre-expressing tissue(s). Because the Snord116 gene cluster is imprinted and only expressed from the paternal allele, breeding 2-loxP males with cre-expressing females may be required to generate deleted offspring with the knockout phenotype. The donating investigator reports that the distance between the two loxP sites (~140 kb) may reduce the recombination efficiency in somatic cells. As deletions of the Snord116 cluster are associated with Prader-Willi syndrome (PWS), mice carrying the 2-loxP (floxed) allele may be useful in generating conditional mutations for studying the role of Snord116 in growth and feeding regulation, mechanisms of obesity, and pathophysiology of Prader-Willi syndrome.

Of note, mice harboring a deletion of the Snord116 cluster are also available (see Stock No. 008149).

For example, when crossed to a strain expressing Cre recombinase in the female germline (see Stock No. 003651), this mutant mouse strain may be useful in studies of Prader-Willi syndrome.

Development

Two individual targeting vectors were used to place a loxP site (and an Frt1-flanked PGK-neo cassette) upstream, and a loxP site (and an Frt5-flanked puromycin resistance/TK cassette) downstream of the Snord116 cluster. The upstream targeting vector was transfected into C57BL/6-derived Bruce-4 embryonic stem (ES) cells, and correctly targeted ES cells were next transfected with the downstream targeting vector. Doubly targeted ES cells were then transiently transfected with an FLP expressing plasmid to remove the two selection cassettes. The resulting 2-loxP ES cells (with a single loxP site just upstream, and a single loxP site just downstream of the Snord116 cluster) were injected into recipient blastocysts. Chimeric males were bred to albino B6(Cg)-Tyr^c-2J/J (Stock No. 000058) females. The resulting females were then bred to C57BL/6 males (expressing cre in the female, but not male, germline (Zp3-cre; Stock No. 003651)). Offspring carrying the 2-loxP mutation (and not the Zp3-cre transgene) were selected and backcrossed to C57BL/6J inbred mice for 2 generations prior to arrival at The Jackson Laboratory.

Allele

Symbol: Snord116^tm1Uta
Name: targeted mutation 1, Uta Francke
MGI accession ID: MGI:3773671
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: 2-lox; 2-loxp
Marker symbol: Snord116
Marker name: small nucleolar RNA, C/D box 116 cluster
Marker synonyms: MBII-85; Pwcr1
Chromosome: 7
Strain of origin: B6.Cg-Thy1^a
Molecular note: Two individual targeting vectors were used to place a loxP site (and an Frt1-flanked PGK-neo cassette) upstream, and a loxP site (and an Frt5-flanked puromycin resistance/TK cassette) downstream of the Snord116 cluster. The upstream targeting vector was transfected into C57BL/6-derived embryonic stem ES cells, and correctly targeted ES cells were next transfected with the downstream targeting vector. Doubly targeted ES cells were then transiently transfected with an FLP expressing plasmid to remove the two selection cassettes. The resulting 2-loxP ES cells with a single loxP site just upstream, and a single loxP site just downstream of the Snord116 cluster.