The Shank3Δ ex4-9 allele has a deletion of the ankyrin repeat domains (exons 4-9) of the Shank3 gene; this deletion prevents full-length Shank3 expression. As Shank3 is necessary for forming functional glutamatergic synapses between receptors and cytoskeletal/scaffolding elements, these mice may be useful for studying synaptic glutamate receptor development/function, transmission and plasticity, as well as Shank3 haploinsufficiency, neurobehavioral manifestations of 22q13 deletion syndrome and/or autism spectrum disorders.
Joseph D Buxbaum, Mount Sinai School of Medicine
These mutant mice harbor a deletion of the SH3/ankyrin domain gene 3 ankyrin repeat domains (exons 4-9). This deletion prevents full-length Shank3 expression; Shank3 mRNA/protein is absent in homozygous postsynaptic density (PSD) fractions, and reduced 50% in heterozygous PSD fractions. Heterozygous mice are viable and fertile with no observed gross brain structure defects or seizures. Heterozygous mice exhibit reduced basal neurotransmission. Heterozygous males display less social sniffing and emit fewer ultrasonic vocalizations during interactions with estrus female mice. Following theta-burst pairing (coincident pre- and postsynaptic stimulation), heterozygous mice have impaired long-term potentiation and altered spine remodeling. Homozygous mice are viable with subtle motor abnormalities. The complete phenotype of homozygous mice is not yet characterized to date (April 2012).
A targeting vector was designed to insert a loxP site upstream of exon 4, and an frt-flanked selection (neo) cassette followed by a second loxP site all downstream of exon 9 of the targeted gene. The construct was electroporated into B6.Cg-Thy1a-derived Bruce4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts. Chimeric males were bred with C57BL/6NTac females to establish the colony. Next, mutant mice were bred with FLP-expressing mice (undisclosed genetic background) to remove the frt-flanked PGK-neo cassette. The resulting Shank3flox ex4-9 mice were subsequently bred to C57BL/6-congenic mice expressing Cre recombinase in embryonic tissues (CMV-Cre; see Stock No. 006054). The resulting mice with pan deletion of the Shank3 ankyrin repeat domains were obtained. These mice were then bred to C57BL/6NTac for two-to-three generations (and the Cre recombinase gene was removed) prior to sending to The Jackson Laboratory Repository. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish The Jackson Laboratory Repository colony. Of note, while backcrossing the donating investigator did not assay their colony at the Thy1 locus. As such, these mice may be segregating for the NZB-derived Thy1a allele (from Bruce4 ES cells) or the C57BL/6-derived Thy1b allele.
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, all 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 1.2, Joseph D Buxbaum|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Shank3, SH3 and multiple ankyrin repeat domains 3|
|Strain of Origin||B6.Cg-Thy1a|
|Molecular Note||A loxP site was inserted upstream of exon 4 and an FRT flanked neo cassette and second loxP site were inserted downstream of exon 9 via homologous recombination. Flp mediated recombination removed the neo cassette. Cre mediated recombination removed exons 4 - 9. Quantitative PCR and immunoblot analysis confirmed the absence of mRNA and protein expression in homozygous mice.|
|Mutations Made By|| |
Joseph Buxbaum, Mount Sinai School of Medicine
Heterozygous males display less social sniffing and emit fewer ultrasonic vocalizations during interactions with estrus female mice. Therefore when maintaining a live colony, heterozygous females may be bred with wildtype males from the colony or with C57BL/6J inbred males (Stock No. 000664).
When using the Shank3- (Shank3Δ ex4-9) mouse strain in a publication, please cite the originating article(s) and include JAX stock #017890 in your Materials and Methods section.