B6.129S1-Atp1a3^Myk/StclJ

Stock number: 032477
Product name: Myshkin , Myk , I810N Myshkin
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

Myshkin (Myk or I810N Myshkin) is an ENU-created, semidominant mutant allele of the Atp1a3 locus harboring two amino acid substitutions D65E and I810N. The I810N mutation renders the normally expressed Na+,K+-ATPase α3 isoform inactive. These mice may be useful in studying epileptiform activity, seizure behavior and neuronal hyperexcitability.
The Jackson Laboratory is unable to ship this strain as live mice due to its severe phenotype. Please contact Customer Service for availability of frozen material.

Detailed description

The semidominant "Myshkin" allele (Myk or I810N Myshkin) is an ENU-created mutation of the Atp1a3 locus harboring two mutations: a T-->A transversion at nucleotide 328 (exon 4) and a T-->A transversion at nucleotide 2562 (exon 18) that are predicted to result in amino acid substitutions Asp⁶⁵³-->Glu (D65E) and Ile⁸¹⁰-->Asn (I810N), respectively. In vitro experiments confirmed that the I810N mutation impairs enzymatic function (renders the normally expressed Na+,K+-ATPase α3 isoform inactive), while D65E does not. After ~4 weeks of age, heterozygous mice (Myk/+) display seizures and neuronal hyperexcitability. Homozygous mice (Myk/Myk) appear grossly normal when born but die shortly after birth.
The donating investigator maintains their colony by breeding wildtype females from the colony or C57BL/6J females with heterozygous males, and this results in normal litters sizes and Mendelian ratios. To offset the colony maintenance challenges resulting from heterozygous seizure incidence, they report it is helpful to separate heterozygous males from wildtype males, as well as to maintain a larger number of breeding cages than usual. In addition, successfully breeding males may be circulated around several pairs of wildtype females.
The donating investigator did not routinely use heterozygous females for breeding. However, this can be achieved by breeding a wildtype littermate male with a heterozygous female and an FVB female. When both females get pregnant at the same time, the FVB female's pups (identified by agouti coat) may be culled and the remaining pups can be fostered by the FVB dam.

In an attempt, to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype of these Myk mice (backcrossed less than five generations onto C57BL/6J) could vary from that originally described on a C57BL/6NCrl congenic background [Clapcote et al. 2009 PNAS 106:14085]. We may modify the strain description if necessary as published results become available.

Researchers using these mice are encouraged to contact the donating investigator for collaboration: Dr. Steven J. Clapcote, University of Leeds (s.j.clapcote@leeds.ac.uk).

Development

ENU mutagenized 129S1/SvImJ (129S1) males were bred to C57BL/6J females. Screening of the F1 population identified a female with a small body. Breeding to C57BL/6NCrl (from NCI-Frederick) showed this phenotype was heritable as a Mendelian autosomal trait, and the small mice exhibited spontaneous, recurrent convulsive seizures as early as 4 weeks of age. When bred to homozygosity, pups appeared grossly normal but died shortly after birth. Detailed characterization (sequencing of genomic DNA and whole brain cDNA) of this semidominant "Myshkin" (Myk) allele revealed it to be the chromosome 7 locus Atp1a3 (α3 isoform of the Na⁺,K⁺-ATPase) harboring two de novo mutations: T-->A transversion at nucleotide 328 (exon 4) and a T-->A transversion at nucleotide 2562 (exon 18) that are predicted to result in amino acid substitutions Asp⁶⁵³-->Glu (D65E) and Ile⁸¹⁰-->Asn (I810N), respectively. In vitro experiments confirmed that the I810N mutation impairs enzymatic function while D65E does not. The donating investigator reports Myk heterozygous males were backcrossed two generations with C57BL/6J females, and then maintained five generations by breeding wildtype females from the colony with heterozygous males. Then embryos were frozen using oocytes from wildtype females from the colony fertilized with sperm from heterozygous males. In 2018, frozen embryos were sent to The Jackson Laboratory Repository as Stock No. 032477. When maintaining our live colony, wildtype females or C57BL/6J females (Stock No. 000664) may be bred with heterozygous males. Additional backcrossing onto C57BL/6J inbred mice (Stock No. 000664) may also be performed.
Of note, the Y chromosome may not have been fixed to the C57BL/6J background during backcrossing.

Allele

Symbol: Atp1a3^Myk
Name: Myshkin
MGI accession ID: MGI:4356167
Generation method: Chemically induced (ENU)
Marker symbol: Atp1a3
Marker name: ATPase, Na+/K+ transporting, alpha 3 polypeptide
Marker synonyms: AHC2; Atpa1a3; Atpa-2; CAPOS; DEE99; DYT12; MGC:27631; MGC:38713; MGC:38914; MGC:39036; RDP
Chromosome: 7
Strain of origin: 129S1/SvImJ
Molecular note: ENU mutagenesis induced point mutations in exons 3 and 17 that encode amino acid substitutions D65E and I810N. The I810N mutation is responsible for the effects on enzyme neurological function. The D65E mutation affects a restriction site.