STOCK Ppt1^tm1.1Dprc/J

Stock number: 026197
Research areas: Cell Biology Research, Developmental Biology Research, Metabolism Research, Neurobiology Research

Description

Cln1^R151X mice contain a nonsense mutation similar to that found in patients with neuronal ceroid lipofuscinoses (NCLs).

Detailed description

Cln1^R151X mice contain the amino acid mutation R151X in exon 5 of the palmitoyl-protein thioesterase 1 (Ppt1) gene. CLN1 is a ubiquitous lysosomal enzyme responsible for removing palmitoyl groups from modified cysteine residues in polypeptides that have been targeted for degradation in the lysosome. Mutations in CLN1 most commonly lead to neuronal ceroid lipofuscinoses (NCL), autosomal recessive neurodegenerative disorder characterized by the progressive onset of seizures, blindness, motor and cognitive decline and premature death. These mutations most commonly lead to infantile NCL in which the patients exhibit microcephaly, seizures, motor abnormalities, ataxia and mental retardation leading to dementia, with death usually occurring by 8 to 13 years of age. Mutations can also lead to other clinical variants of NCL, such as variant forms of late-infantile NCL, juvenile NCL, and adult NCL.

In these mice, the R151X mutation introduces a nonsense mutation analogous to a Cln1 mutation commonly found patients with NCL. CLN1 proteins harboring the R151X mutation are targeted for degradation by the nonsense-mediated decay (NMD) pathway, leading to a significant decrease in CLN1 mRNA level and concurrent decrease in CLN1 enzyme activity in patient-derived lymphoblast cell lines. Tissues from heterozygous Cln1^R151X mice showed a 1.42- to 1.85-fold decrease in Cln1 expression and tissues from homozygotes showed a 5.32- to 12.99-fold decrease in Cln1 expression. Mice display significant motor deficits by 3 months of age. They also have significant accumulation of autofluorescent storage material within the cortex, thalamus and hippocampus at 5 months of age, consistent with the neuropathological hallmarks of infantile NCL disease.

Development

A targeting construct was designed to insert a C to T point mutation in exon 5 of the palmitoyl-protein thioesterase 1 (Ppt1) gene, resulting in a non-sense mutation, R151X, commonly found in humans with neuronal ceroid lipofuscinoses (NCLs). A loxP- and frt-flanked neomycin (neo) resistance cassette was inserted downstream of exon 5. This targeting construct was electroporated into 129S6/SvEv x C57BL/6J-derived embryonic stem (ES) cells and correctly targeted ES cells were injected into blastocysts. The resulting chimeric mice were bred to B6.C-Tg(CMV-cre)1Cgn/J (Stock No. 006054) to remove the floxed neo selection cassette, and offspring were crossed to remove the cre-expressing transgene. These Cln1^R151X mice were maintained on a mixed background. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Ppt1^tm1.1Dprc
Name: targeted mutation 1.1, David Pearce
MGI accession ID: MGI:5585301
Generation method: Targeted
Attributes: Humanized sequence
Marker symbol: Ppt1
Marker name: palmitoyl-protein thioesterase 1
Chromosome: 4
Strain of origin: 129S6/SvEvTac x C57BL/6J
Expressed genes: Ppt1,palmitoyl-protein thioesterase 1,mouse, laboratory
Molecular note: A targeting construct was designed to insert a C to T point mutation in exon 5 of the gene, resulting in a non-sense mutation, R151X, commonly found in humans with neuronal ceroid lipofuscinoses (NCLs). A loxP- and frt-flanked neomycin (neo) resistance cassette was inserted downstream of exon 5. Cre-mediated recombination removed the floxed neomycin cassette.