B6.129S(Cg)-Ank3^tm3.1Bnt/J

Stock number: 029798
Product name: Ank3 floxed exon 37 (480-kDa isoform)
Research areas: Neurobiology Research, Research Tools

Description

Exon 37, the "giant exon" of the Ankyrin-G (Ank3) gene, is flanked by loxP sites in this conditional mutant strain. Cre-mediated excision of the floxed region blocks the expression of a 480-kDa isoform.

Detailed description

Ankyrin-G (Ank3, ankyrin 3, epithelial) is a critical adaptor protein that acquired a "giant exon" early in vertebrate evolution, resulting in a new nervous system-specific polypeptide that is a master organizer of axonal excitable membranes.

Exon 37, the giant exon contributing to the expression of a 480-kDa isoform, is flanked by loxP sites in this conditional mutant allele (PMID 25552556).

When the floxed region was excised through crosses with a Nes-cre strain (see Stock No. 003771), mice exhibited a loss of the giant exon-encoded sequence from the majority of brain areas examined by the donating laboratory. Loss of Exon 37 resulted in loss of all known components of axon initial segments as well as major malformation of nodes of Ranvier in myelinated CNS axons. Expression in the dentate gyrus, optic nerve, sciatic nerve, and the majority of the spinal cord was spared. Giant exon-null mice survive through weaning, living up to 20 days, whereas total Ank3-null mice crossed with the same Nes-cre line died immediately after birth. Western blots from whole-brain lysates confirmed a greater than 90% loss of 480- and 270-kDa giant Ank3 isoforms. However, giant exon-null mice had a four- to fivefold increase in expression of 190-kDa ANK3 as well as a 210-kDa splice variant containing an additional 195 amino acids.

Development

A loxP site was placed in intron 36 and an FRT-loxP-neomycin-FRT-loxP cassette was introduced to intron 37 via homologous recombination in 129S6/SvEvTac-derived TL1 embryonic stem (ES) cells. Resultant chimeric mice were bred to a FLP recombinase-expressing strain to excise the neomycin site, then backcrossed to a C57BL/6 inbred strain for 5 generations by the donating laboratory.

Allele

Symbol: Ank3^tm3.1Bnt
Name: targeted mutation 3.1, Vann Bennett
MGI accession ID: MGI:5829555
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: Exon 37^fl
Marker symbol: Ank3
Marker name: ankyrin 3, epithelial
Marker synonyms: 2900054D09Rik; ANK-3; AnkG; Ankyrin-3; Ankyrin-G; MRT37
Chromosome: 10
Strain of origin: 129S6/SvEvTac
Molecular note: A loxP site was placed in intron 36 and an FRT-loxP-neomycin-FRT-loxP cassette was introduced to intron 37 via homologous recombination. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exon 37 floxed. The version of this allele that contains the neomycin selection cassette, Ank3^tm3Bnt, has been analyzed.