Homozygous Snap25 knock-out mice exhibit neonatal lethality. Late embryos lack spontaneous movement or sensorimotor reflexes, and abnormal innervation and muscle fiber development is observed.
Michael C. Wilson, University of New Mexico
Genetic Background | Generation |
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|
Allele Type | Gene Symbol | Gene Name |
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Targeted (Null/Knockout) | Snap25 | synaptosomal-associated protein 25 |
Homozygous mutant mice die at birth from respiratory failure. At embryonic day 17.5 to 18.5 homozygous embryos appear smaller and do not display spontaneous movement or sensorimotor reflexes. Dilated vascular channels in subcutaneous tissues give the embryos an external blotchy appearance. No gene product (mRNA or protein) is detected by Northern or Western blot analysis of brain tissue from homozygous animals. Histological analysis of fetal diaphragm tissue reveals a dispersed pattern of innervation and fewer layers of muscle fibers. Thin, disarrayed intercostal and anterior chestwall muscles are also observed. Spontaneous miniature endplate potential (mEPP) activity is detected in the diaphragm phrenic nerve, but no evoked endplate potentials (EPP), evoked neurotransmitter release or muscle contraction is detected with stimulation of the neuromuscular junction (NMJ). Mutant NMJs exhibit larger endplate diameters and lower levels of acetylcholinesterase. Tetrodotoxin (TTX) resistant miniature excitatory postsynaptic currents (mEPSCs), but not evoked, action-potential dependent responses are detected from mutant central nervous system (CNS) synapses. Mice that are heterozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. Thismutant mouse strain may be useful in studies of neuroexocytosis and neurotransmitter release in the developing nervous system.
A targeting vector containing neomycin resistance and herpes simplex virus thymidine kinase genes was used to disrupt exons 5a and 5b and part of the downstream intron. The construct was electroporated into 129X1/SvJ derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6 mice, and then backcrossed to C57BL/6 for 7 generations (September 2003).
Allele Name | targeted mutation 1, Michael C Wilson |
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Allele Type | Targeted (Null/Knockout) |
Allele Synonym(s) | Snap25- |
Gene Symbol and Name | Snap25, synaptosomal-associated protein 25 |
Gene Synonym(s) | |
Strain of Origin | Not Specified |
Chromosome | 2 |
Molecular Note | Exon 5a/b and part of the downstream intron were replaced with a PGK-neo cassette by homologous recombination. Western blot of brain proteins and RT-PCR analysis of total brain RNA from homozygous mutant embryos verified the absence of gene expression. |
Mutations Made By | Michael Wilson, University of New Mexico |
This strain originated on a B6;129 background and was backcrossed to C57BL/6 for 7 generations (September 2003). The strain must be maintained as a heterozygote. Homozygotes are not viable.
When using the SNAP-25 KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #004863 in your Materials and Methods section.
Facility Barrier Level Descriptions
Service/Product | Description | Price |
---|---|---|
Heterozygous or Wild-type for Snap25<tm1Mcw> |
Frozen Mouse Embryo | B6.129X1-Snap25<tm1Mcw>/J Frozen Embryos | $2595.00 |
Frozen Mouse Embryo | B6.129X1-Snap25<tm1Mcw>/J Frozen Embryos | $2595.00 |
Frozen Mouse Embryo | B6.129X1-Snap25<tm1Mcw>/J Frozen Embryos | $3373.50 |
Frozen Mouse Embryo | B6.129X1-Snap25<tm1Mcw>/J Frozen Embryos | $3373.50 |
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The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project. We do not guarantee breeding performance and therefore suggest that investigators order more than one breeding pair to avoid delays in their research.
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