C57BL/6J-Nhlrc1^em1Cwor/J

Stock number: 036238
Product name: Malin D148N

Strain synonyms: Nhlrc1 D148N , Nhlrc1*D148N , Nhlrc1-D148N , Nhlrc1^D148N , Malin*D148N , Malin-D148N , Malin^D148N
Research areas: Mouse/Human Gene Homologs, Neurobiology Research

Description

Malin D148N knock-in mice express the D148N (aspartic acid to asparagine) amino acid substitution in the Nhlrc1 (NHL repeat containing 1 or malin) locus. Mice homozygous for the mutation develop Lafora bodies upon aging. Loss of function mutations in NHLRC1 are associated with Lafora disease, a rare and severe form of progressive myoclonus epilepsy.

Detailed description

Nhlrc1 (NHL repeat containing 1 or malin or EPM2B) encodes a E3 ubiquitin ligase involved in the regulation of glycogen metabolism. Specifically, malin and the phosphatase, laforin (Epm2a), form a complex that prevents glycogen hyperphosphorylation and the formation of neurotoxic insoluble aggregates called Lafora bodies. Loss of function mutations in malin, such as D146N (corresponding to mouse D148N), are associated with Lafora disease, a rare and severe form of progressive myoclonus epilepsy.  Lafora disease is characterized by epileptic seizures in late childhood or adolescence, difficulty walking, muscle spasms (myoclonus), dementia and death within 10 years of disease onset.

Malin D148N knockin mice were created using CRISPR/cas9 genome editing to express the D148N (aspartic acid to asparagine) amino acid (aa) substitution in the Nhlrc1 locus. Homozygous mice are viable and fertile. Homozygotes develop Lafora bodies in the cerebellum, hippocampus, heart and skeletal muscle upon aging. In addition, glycogen is increased by approximately 3-fold in skeletal muscle and 2-fold in brain as compared to wild-type.

Of note, mice carrying the R240X substitution in laforin (Epm2a) are available as Stock No. 036199.

Development

CRISPR/cas9 endonuclease-mediated genome editing was used to create an amino acid substitution at position 148 (aspartic acid to asparagine, D148N) in the Nhlrc1 locus on chromosome 13. Single guide RNA and cas9 endonuclease were introduced into C57BL/6J-derived fertilized eggs by pronuclear injection. Embryos were transferred to pseudopregnant females, and correctly targeted pups were bred to C57BL/6J mice for germline transmission. The colony was maintained on the C57BL/6J background. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.

Allele

Symbol: Nhlrc1^em1Cwor
Name: endonuclease-mediated mutation 1, Carolyn Worby
MGI accession ID: MGI:6828603
Generation method: Endonuclease-mediated
Attributes: Humanized sequence
Synonyms: Malin D148N
Marker symbol: Nhlrc1
Marker name: NHL repeat containing 1
Marker synonyms: B230309E09Rik; bA204B7.2; Epm2b; MALIN; MELF2
Chromosome: 13
Strain of origin: C57BL/6J
Molecular note: CRISPR/cas9 endonuclease-mediated genome editing was used to create an amino acid substitution at position 148 (aspartic acid to asparagine, D148N). Loss of function mutations in malin, such as D146N (corresponding to mouse D148N), are associated with Lafora disease, a rare and severe form of progressive myoclonus epilepsy.