BK β2 floxed mice possess loxP sites flanking exon 1 of the Kcnmb2 gene, making this strain useful for studying the regulation of BK channel activation.
Christopher J. Lingle, Washington University School of Medicine
BK β2 floxed mutant mice possess loxP sites flanking exon 1 of potassium large conductance calcium-activated channel, subfamily M, beta member 2 (Kcnmb2) gene, which includes the coding sequence of the β2 subunit N terminus. KCNMB2 encodes the regulatory β2 subunit of the calcium activated potassium KCNMA1 channel, which produces inactivation of BK channels. In adrenal chromaffin cells, this subunit also shifts the activation range of β2-containing BK channels to more negative voltages, thereby enhancing afterhyperpolarizations and helping sustain repetitive firing. BK β2 floxed mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have first exon and start codon deleted in cre-expressing tissues.
A targeting vector was designed by Dr. Xiao-Ming Xia (laboratory of Dr. Christopher Lingle Washington University School of Medicine) to insert a loxP site upstream of exon 1 of the potassium large conductance calcium-activated channel, subfamily M, beta member 2 (Kcnmb2) gene. The construct also inserted a second loxP site, followed by a frt-flanked neomycin resistance (neo) cassette which included a third loxP site, downstream of exon 1. The construct was electroporated into C57BL/6-derived BLU embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric mice were bred with B6.Cg-Tg(Pgk1-FLPo)10Sykr/J transgenic mice (Stock No. 011065) to delete the neo cassette. Resulting progeny were crossed to remove the Flp-expressing transgene, and BK β2 floxed offspring were backcrossed to C57BL/6J mice for at least 12 generations. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 1.1, Christopher J Lingle|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Allele Synonym(s)||beta2floxed; kcnmb2 floxed|
|Gene Symbol and Name||Kcnmb2, potassium large conductance calcium-activated channel, subfamily M, beta member 2|
|Strain of Origin||C57BL/6NTac-Tg(HBB-lacZ)ALey/Ley|
|Molecular Note||A targeting vector was designed to insert a loxP site upstream of exon 1 and a second loxP site downstream of exon 1 followed by an FRT-flanked neomycin resistance (neo) cassette which included a third loxP site, downstream of exon 1. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exon 1 floxed.|
When maintaining a live colony, homozygous mice may be bred together.
When using the BK β2 floxed mouse strain in a publication, please cite the originating article(s) and include JAX stock #028416 in your Materials and Methods section.