B6;129P2-Syt1^tm3Sud/J

Stock number: 006385
Product name: R233Q KI
Research areas: Neurobiology Research

Description

These Syt1 knock-in mice exhibit altered Ca²⁺ protein affinity and sensitivity of neurotransmitter release. They are useful in studies of synaptic neurotransmission.

Detailed description

Mice homozygous for this targeted point mutation are viable and fertile and do not display any gross physical or behavioral abnormalities. The mutant gene is fully expressed. A two-fold decrease in the overall Ca²⁺ affinity of the protein and a corresponding decrease in the Ca²⁺ sensitivity of neurotransmitter release is observed. Nuclear Magnetic Resonance (NMR) spectroscopy shows no structural or conformational changes in the mutant protein. This mutant mouse strain represents a model that may be useful in studies of synaptic neurotransmitter release.

Development

A targeting vector was used to create an R233Q substitution in the exon encoding residues 214-269 and insert a floxed neomycin resistance gene into the flanking intron. The construct was electroporated into 129P2/OlaHsd-derived E14.1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. Chimeric animals were crossed with C57BL/6. The strain has been minimally backcrossed to C57BL/6 by the donating laboratory.

Allele

Symbol: Syt1^tm3Sud
Name: targeted mutation 3, Thomas C Sudhof
MGI accession ID: MGI:2180148
Generation method: Targeted
Marker symbol: Syt1
Marker name: synaptotagmin I
Chromosome: 10
Strain of origin: 129P2/OlaHsd
Molecular note: Insertion of a neomycin resistance cassette into intron 1 and an arginine to glutamine point mutation at position 233 of exon 1 (R233Q) was introduced via homologous recombination. Western blot of brain homogenates from homozygous mutant animals verified the presence of protein expression and enzyme assays demonstrated similar phospholipid- and syntaxin-binding ability compared to wild-type. However, calcium affinity was decreased by 2-fold.