Arid1b Flox (Arid1bFl; floxed exon 5) mice have a CRISPR/cas9-generated, Cre-conditional knock-out allele. These mice may be useful in studying the SWI/SNF chromatin-remodeling complex, autism spectrum disorder, intellectual disability, corpus callosum agenesis and Coffin-Siris syndrome.
Hao Zhu, University of Texas Southwestern Medical Center [UTSW]
ARID1B is a SWI/SNF chromatin-remodeling subunit. ARID1B haploinsufficiency in humans is associated with autism spectrum disorder, intellectual disability, corpus callosum agenesis and short stature. In addition, ARID1B mutation is the most common cause of Coffin-Siris syndrome.
The Arid1b Flox allele (Arid1bFl) has loxP sites flanking exon 5. Mice homozygous for this floxed allele are viable and fertile, with no reported gross phenotypic or behavioral abnormalities.
Upon exposure to Cre recombinase, the floxed sequences are deleted - resulting in a null allele (Arid1bΔ).
For example, when Arid1b Flox are bred to Nestin-Cre transgenic mice (e.g., Stock No. 003771), the resulting brain-specific ARID1B haploinsufficiency (Nestin-Cre; Arid1bFl/+) leads to growth impairment and reduced plasma insulin-like growth factor (IGF1) levels with inappropriate lack of growth hormone (GH) increase - characteristics of ARID1B mutation in humans. [Celen et al. 2017 Elife 6:e25730]
Furthermore, breeding Arid1b Flox to mice with liver-specific or skeletal muscle-specific Cre-expression (Stock Nos. 003574 or 006475, respectively) generates mice with tissue-specific ARID1B haploinsufficiency. In the resulting offspring, neither Albumin-Cre; Arid1bFl/+ nor Ckmm-Cre; Arid1bFl/+ showed growth or morphological defects. [Celen et al. 2017 Elife 6:e25730]
In addition, breeding Arid1b Flox to germline Cre-expressing mice (e.g., Sox2-Cre; Stock No. 008454) should generate mice with the ARID1B global knock-out allele. Mice homozygous or heterozygous for the global knock-out allele can be expected to have the same phenotype as other ARID1B whole-body knock-out alleles. That is, homozygotes are perinatal lethal, while heterozygotes are viable and fertile with social behavior impairment, altered vocalization, anxiety-like behavior (increased self-grooming), neuroanatomical abnormalities and growth impairment. Approximately 7% of mice heterozygous for a whole-body knock-out of the gene also have hydrocephaly.
The Arid1b Flox allele (Arid1bFl; floxed exon 5) was created in the laboratory of Dr. Hao Zhu (University of Texas Southwestern Medical Center) using CRISPR/cas9 endonuclease-mediated genome editing. Guide RNAs were designed to target sequences before and after exon 5 of the AT rich interactive domain 1B [SWI-like] locus (Arid1b) on chromosome 17. The guide RNAs, oligo donors containing loxP sequences and S. pyogenes CRISPR/cas9 mRNA were injected into single-celled C57BL/6J zygotes. Founder mice with the Arid1b Flox allele (loxP::exon5::loxP) were identified by PCR and sequencing of the Arid1b exon5 region. Founders were bred to C57BL/6J mice for germline transmission. The Arid1b Flox colony was backcrossed to C57BL/6J for approximately five generations, and then bred together as homozygotes. To date (May 2018), these mice have not been characterized for off-target mutations. In 2018, males with black coat color were sent to The Jackson Laboratory Repository. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
A 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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. One of the 27 markers throughout the genome were segregating with 129. Also, all 4 of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating with an unknown source. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.
|Allele Name||endonucelase mediated mutation 2, Hao Zhu|
|Allele Type||Endonuclease-mediated (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Arid1b, AT rich interactive domain 1B (SWI-like)|
|Strain of Origin||C57BL/6J|
|Molecular Note||LoxP sites were inserted surrounding exon 5.|
Mice homozygous for the Arid1b Flox allele are viable and fertile, with no reported gross phenotypic or behavioral abnormalities. When maintaining a live colony, heterozygous mice may be bred together, to wildtype mice from the colony or to C57BL/6J inbred mice (Stock No. 000664). Alternatively, homozygous mice may be bred together.
When using the Arid1b Flox (Arid1bFl; floxed exon 5) mouse strain in a publication, please cite the originating article(s) and include JAX stock #032061 in your Materials and Methods section.