These mice possess loxP sites flanking exon 3 of βII-spectrin. This strain may be useful for studying distal axon-cytoskeleton interactions and functions.
Matthew N. Rasband, Baylor College of Medicine
Spnb2fl/fl mutant mice possess loxP sites flanking exon 3 of the spectrin beta, non-erythrocytic 1 (Sptbn1) gene. βII-spectrin is a molecular scaffold protein located in the distal regions of the axon where it links the plasma membrane to the actin cytoskeleton. βII-spectrin plays a role in neuron axonal polarity and growth by linking axon initial segments (AISs) to the cytoskeleton. Homozygotes are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exon 3 deleted in the cre-expressing tissues. Widespread deletion results in embryonic lethality.
When bred to B6.Cg-Tg(Nes-cre)1Kln/J mice (Stock No. 003771) with neuronal cre-expression, resulting mice exhibit significant fragmentation and disruption of AIS in the hippocampus and cortex.
A targeting vector was designed to insert a frt-flanked neomycin resistance (neo) cassette and a loxP site upstream of exon 3, and a second loxP site downstream of exon 3 of the spectrin beta, non-erythrocytic 1 (Sptbn1) gene. The construct was electroporated into 129S7/SvEvBrd-Hprtb-m2-derived AB2.2 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts and resulting chimeric mice were bred to C57BL/6J mice. Offspring were bred with 129S4/SvJaeSor-Gt(ROSA)26Sortm1(FLP1)Dym/J (Stock No. 003946) transgenic mice to delete the neo cassette, and progeny were crossed to remove the Flp-expressing transgene. These Spnb2fl/fl mice were maintained on a mixed C57BL/6J;129 background. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.
|Allele Name||targeted mutation 1.1, Matthew N Rasband|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Sptbn1, spectrin beta, non-erythrocytic 1|
|Strain of Origin||129S7/SvEvBrd-Hprtb-m2|
|Molecular Note||Exon 3 was floxed and an FRT-flanked neo cassette was removed by flp-mediated recombination.|
When maintaining a live colony, homozygous mice may be bred together.
When using the B6;129S-Sptbn1tm1.1Mnr/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #020288 in your Materials and Methods section.