Homozygous Parkinson disease (autosomal recessive, juvenile) 2, parkin (Park2tm1Shn) knock-out mice have increased extracellular dopamine concentration in the striatum, dysfunctional nigrostriatal pathways, and dysfunctional mitochondria. These mice model the exon 3 deletion mutation most common in human autosomal recessive juvenile parkinsonism patients and may be useful in studies of Parkinson's disease, dopamine regulation, nigrostriatal function, mitochondrial function, and other neurobiological research.
Jie Shen, Harvard Med Sch/Brigham Women's Hosp
Homozygous mice are viable and fertile, and exhibit grossly normal brain morphology. Western blot analysis using antibody specific to C-terminal sequences indicates the absence of full length gene product. RT-PCR shows that exon 2 splices to exon 4, skipping exon 3 entirely, resulting in a frame shift and a premature stop codon in exon 5. While EGFP transcripts are present, little parkin-EGFP fusion protein is detectable by Western analysis. Homozygous mice have increased extracellular dopamine concentration in the striatum. Further, medium-sized striatal spiny neurons require greater currents to induce synaptic responses, suggesting a reduction in synaptic excitability in the absence of the endogenous gene. Homozygotes also exhibit deficits in behavioral paradigms sensitive to dysfunction of the nigrostriatal pathway. The numbers of dopaminergic neurons in the substantia nigra, however, are normal up to the age of 24 months, in contrast to the substantial loss of nigral neurons characteristic of Parkinson's disease. Homozygous mice and their isolated cells exhibit mitochondrial dysfunction and impaired protection from oxidative stress. Muscle cells isolated from homozygous mice have defective skeletal muscle mitochondrial homeostasis and increased sensitivity to amyloid-beta toxicity. These mice model the exon 3 deletion mutation most common in human autosomal recessive juvenile parkinsonism (AR-JP) patients and may be useful in studies of Parkinson's disease, dopamine regulation, nigrostriatal function, mitochondrial function, and other neurobiological research.
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. Mice with this mutation were originally published on a mixed B6;129S4 genetic background. It should be noted that the phenotype could vary from that originally described. The strain description will be modified as published results become available.
A targeting vector was designed to replace most of exon 3 of the endogenous gene with the in-frame EGFP coding sequence (followed by translation and transcription termination sequences and a PGK-neomycin cassette). The construct was electroporated into the 129S4/SvJae-derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The donating investigator reported that the resulting mutant mice were backcrossed to C57BL/6 (see SNP note below) inbred mice for more than 20 generations before arriving at The Jackson Laboratory.
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 2 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.
|Allele Name||targeted mutation 1, Jie Shen|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||Park2tm1Shn; parkin -|
|Gene Symbol and Name||Prkn, parkin RBR E3 ubiquitin protein ligase|
|Strain of Origin||129S4/SvJae|
|Molecular Note||Exon 3 was replaced in-frame by the coding sequence for EGFP followed by a PGK-neomycin cassette. RT-PCR analysis indicated that exon 2 spliced to exon 4 in transcripts thus skipping exon 3 entirely. This results in a frame shift and a premature stop codon in exon 5. Western blot analysis using antibody specific to C-terminal sequences indicated the absence of gene product.|
|Mutations Made By|| |
Jie Shen, Harvard Med Sch/Brigham Women's Hosp
When maintaining a live colony, homozygous mice may be bred together.
When using the parkin- mouse strain in a publication, please cite the originating article(s) and include JAX stock #006582 in your Materials and Methods section.