B6.129-Kcnn1^tm1.2Jpad/J

Stock number: 009591
Research areas: Cell Biology Research, Neurobiology Research, Research Tools

Description

The SK1-flox (delta neo) allele has loxP sites flanking the coding sequences of exons 3-5 (and an enhanced green fluorescent protein (EGFP) coding sequence just downstream of the second loxP site) in the Kcnn1 (also called SK1) locus. This allele is reported to have no EGFP expression and likely confers a null phenotype even before exposure to Cre recombinase. When bred to mice that express Cre recombinase, the SK1 sequences encoding the translation initiation site through transmembrane domain five are deleted in the cre-expressing tissues of the offspring. These SK1-flox (delta neo) mutant mice may be useful in studying the role of small-conductance calcium-activated potassium (SK) channels in after-hyperpolarization and action potentials in neurons, as well as synaptic plasticity and spatial and non-spatial memory.

Detailed description

Homozygous SK1-flox (delta neo) mice are viable and fertile, with loxP sites flanking the coding sequences of exons 3-5 (and an enhanced green fluorescent protein (EGFP) coding sequence just downstream of the second loxP site) in the Kcnn1 (also called SK1) locus. The donating investigator reports that homozygotes exhibit no overt phenotype and that the SK1-flox (delta neo) allele may confer a null phenotype even before exposure to Cre recombinase: RT-PCR shows the EGFP sequence disrupts splicing such that no full length transcripts are detected. No EGFP expression is reported. When bred to mice that express Cre recombinase, the SK1 sequences encoding the translation initiation site through transmembrane domain five are deleted in the cre-expressing tissues of the offspring. These SK1-flox (delta neo) mutant mice may be useful in studying the role of small-conductance calcium-activated potassium (SK) channels in after-hyperpolarization and action potentials in neurons, as well as synaptic plasticity and spatial and non-spatial memory.

Development

A targeting vector was designed to place a loxP site into the 5' UTR 40 nucleotides upstream of the initiator methionine codon in exon 3, as well as a loxP-flanked neo cassette and enhanced green fluorescent protein (EGFP) coding sequence in intron 5 of the targeted gene. A hemagglutinin (HA) epitope tag was also inserted into the coding sequence into the extracellular loop between transmembrane spanning domains 1 and 2. The donating investigator reports that this construct was electroporated into 129/Sv-derived embryonic stem (ES) cells (probably 129S4/SvJae-derived J1 ES cells). Correctly targeted ES cells were injected into recipient blastocysts and chimeric mice were bred with C57BL/6J mice. SK1-flox mice were then backcrossed to C57BL/6J for 8-9 generations. Next, SK1-flox mice were bred to a Cre deleter strain (MeuCre40; reported to be on a C57BL/6 genetic background) and the floxed neo cassette was removed. The resulting SK1-flox (delta neo) mutant mice (still harboring loxP-flanked exons 3-5 and an EGFP just downstream of the second loxP site) were subsequently backcrossed to C57BL/6J for at least 9 generations (and the Cre transgene was removed) prior to sending to The Jackson Laboratory. Upon arrival, mutant mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Kcnn1^tm1.2Jpad
Name: targeted mutation 1.2, John P Adelman
MGI accession ID: MGI:4431001
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Kcnn1
Marker name: potassium intermediate/small conductance calcium-activated channel, subfamily N, member 1
Chromosome: 8
Strain of origin: Not Specified
Molecular note: A loxP site was inserted 40 nucleotides 5' of the initiation methionine codon in exon 3 and a floxed neomycin resistance gene as well as an EGFP gene were inserted in the intron between exons 5 and 6. The EGFP insert was non functional. Cre mediated recombination removed the neo cassette leaving the loxP sites in exon 3 and intron 5 intact.