STOCK Del(7Coro1a-Spn)1Dolm/J

Stock number: 025100
Product name: 16p11.2^-
Strain synonyms: 16p11^-
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools, Sensorineural Research

Description

A copy number variation on human chromosome 16p11.2 is among the most common genetic variations found in autism spectrum disorders. The 16p11^- allele has the syntenic 440 kbp region on mouse chromosome 7F3 deleted (between and including Coro1a to Spn) and also expresses a fluorescent reporter gene (mCherry) under the control of the CAG promoter. These mice may be useful in studying basal ganglia circuitry and the pathophysiology of autism.

Detailed description

This strain description is for 16p11^- mice on a predominantly C57BL/6N genetic background. Because the live colony at The Jackson Laboratory is maintained by breeding B6129SF1/J (Stock No. 101043) with heterozygous 16p11^- males every generation, the phenotype of the 16p11^- mice distributed from The Jackson Laboratory Stock No. 025100 could vary from that shown below. We may modify the strain description if necessary as published results become available.

A copy number variation (CNV) on human chromosome 16p11.2 is among the most common genetic variations found in autism spectrum disorders (ASD). Patients with this deletion display motor deficits, speech/language delay, and cognitive impairments, accompanied by ASD, attention deficit hyperactivity disorder (ADHD), seizures, and hearing disorders. Conversely, a duplication of 16p11.2 is associated with schizophrenia. The chromosome 16p11.2 CNV encompasses 26 genes that are highly conserved on mouse chromosome 7F3.

The 16p11^- allele has the syntenic 440 kbp region on mouse chromosome 7F3 deleted (between and including Coro1a to Spn) and also expresses a membrane-targeted fluorescent reporter gene (mCherry) under the control of the CAG promoter. Heterozygous mice (16p11^+/-) are viable and fertile, but are visibly smaller and leaner with impaired early postnatal survival (see additional breeding notes below). 16p11^+/- mice exhibit normal social behavior but show hyperactivity, circling and deficits in movement control, hearing (deaf), and habituation to familiarity. Heterozygotes have anatomical and cellular abnormalities, particularly in cortex and striatum of juvenile mice: abnormalities in the basal ganglia circuitry, elevated dopamine D2 receptor (Drd2+) expressing striatal medium spiny neurons and fewer dopamine-sensitive (Drd1+) neurons in deep layers of cortex. For imaging large-scale anatomical structures, such as white matter tracts, mCherry fluorescence is very strong. For identification of single neuronal cell-bodies, however, immunohistochemical fluorescence might improve the outcome.

The donating investigator reports the following breeding characteristics. Heterozygous females do not take care of their pups. Breeding 16p11^+/- animals together never resulted in homozygous pups. To improve pup survival, breeding cages may be supplemented with high-fat chow and fresh fruit (apples and oranges). Removing wildtype littermates by postnatal day 6 reduces food competition and is very effective in improving 16p11^+/- pup survivability. Further, 16p11^+/- pups benefit from concentrated liquid dietary supplement and vitamin B12 injections (if underweight). Heterozygous mice are usually still runty at standard weaning age, and benefit from delaying wean for up to a week. All weanlings may be provided with fresh fruit supplements until 4 weeks of age. Healthy adults can be maintained on standard rodent chow and water ad libitum. Underweight adults benefit from dietary supplements.

Mice with the mouse chromosome 7F3 region flanked by several loxP and frt sites (16p11^flx) are available at The Jackson Laboratory as Stock No. 025330.

Development

The 16p11^- allele has a deletion of the 440 kbp region on mouse chromosome 7F3 (between and including Coro1a to Spn); a region highly conserved with the human chromosome 16p11.2 region whose copy number variations are associated with autism spectrum disorders and schizophrenia.

Drs. Ricardo E. Dolmetsch and Thomas Portmann (while at Stanford University) created the two targeting vectors used to generate these 16p11^- mice. The first vector was designed to insert a CMV-IE enhancer/chicken beta-actin/rabbit beta-globin hybrid promoter (from pCAGGS), loxP-frt-neomycin resistance cassette-loxP-frt-loxP sequence and polyA signal at the centromeric end of the coronin actin binding protein 1A locus (Coro1a). The insertion site was 1165 bp centromeric (transcriptionally downstream) of the last Coro1a exon to avoid disrupting endogenous expression prior to Cre recombination. The second targeting vector was designed to insert a translational stop codon (for all frames), loxP-frt-puromycin resistance cassette-loxP-frt sequence, rabbit b-globin intron, coding sequence mCherry fluorescent protein (with palmitoylation signal for membrane targeting) and polyA signal at the telomeric end of the sialophorin locus (Spn). The insertion site was 3336 bp telomeric (transcriptionally upstream) of the Spn gene to avoid disrupting endogenous expression prior to Cre recombination. Sequential targeting into 129 mouse embryonic stem cells (mESC [see note below]) resulted in mESC clones with cis arrangement (targeting into the same chromosome 7 homolog) or trans arrangement (each vector targeted into different chromosome 7 homologs). The modified mESCs were injected into blastocysts, implanted into pseudopregnant female mice, and chimeric males were subsequently bred to C57BL/6NCrl females and/or HPRT-Cre females (Hprt^tm1(cre)Mnn on a C57BL/6;CD1 mixed genetic background; see Stock No. 004302). Germline transmission was successful only for the cis arrangement, and animals lacking one copy of the 16p11 genes resulted in heterozygous deletion mice (16p11^+/-). Dr. Dolmetsch bred the 16p11^+/- colony onto C57BL/6NCrl for at least three generations, and then sent 16p11^+/- mice to Dr. Jacqueline N. Crawley (while at NIMH) in 2011. Dr. Crawley took the colony to University of California Davis in 2012. Dr. Crawley maintained the colony by breeding wildtype (16p11^+/+) females with 16p11^+/- males every generation (with one mating of C57BL/6J females to 16p11^+/- males in 2013). In 2014, Dr. Crawley sent The Jackson Laboratory 16p11^+/- males on a mixed genetic background (~67% C57BL/6N, ~30% 129 [not all from 129P origin], ~3% C57BL/6J, and a region of chromosome 7 that is neither C57BL/6 nor 129 [may be CD1]). Upon arrival, sperm from an agouti male was cryopreserved. To establish our living colony, an aliquot of frozen sperm was used to fertilize B6129SF1/J oocytes (Stock No. 101043). When maintaining a live colony at The Jackson Laboratory, B6129SF1/J (Stock No. 101043) females are bred with heterozygous males every generation.

Although the Portmann et al. 2014 Cell Rep 7(4):1077-92 publication describes the mESC used were 129/OLA, the donating laboratory indicates it may have been a different 129 origin. It is not known if the 16p11^+/- mice we received retained the mESC-derived allele(s) at the tyrosinase locus (e.g., Tyr^c and/or Tyr^c-ch) that, because it is only ~40 kbp proximal on chromosome 7, would segregate along with the 16p11^- region.

Allele

Symbol: Del(7Coro1a-Spn)1Dolm
Name: deletion, Chr 7, Ricardo Dolmetsch 1
MGI accession ID: MGI:5569506
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Del(7Coro1a-Spn)1Dolm
Marker name: deletion, Chr 7, Ricardo Dolmetsch 1
Chromosome: 7
Strain of origin: 129P2/OlaHsd
Expressed genes: RFP,Red Fluorescent Protein,coral
Site of expression: Basal ganglia in cortex and striatum of juvenile mutant mice.
Molecular note: Two sequential targeting events generated Igs14^tm1Dolm and Igs13^tm1Dolm. Cre-mediated recombination removed both floxed neomycin cassettes creating a deletion that spans 440 kbp region on mouse chromosome 7F3 (between and including Coro1a to Spn); a region highly conserved with the human chromosome 16p11.2 region whose copy number variations are associated with autism spectrum disorders and schizophrenia.