This CBPdeltaCH1 mutant strain carries a deletion mutation in the exon encoding the CH1 domain of the Crebbp gene, resulting in the disruption in the ability of the CREB binding protein to bind transcriptional regulators. This strain may be useful in studies of transcriptional regulation and Autism Spectrum Disorders.
Paul K. Brindle, St. Jude Children's Research Hospital
The Crebbp gene encodes the CREB binding protein and the Ep300 gene encodes the E1A binding protein p300, both of which are highly conserved coactivators that promote transcription and are important to the function of many hematopoietic transcription factors. These CBPdeltaCH1 mutant mice carry an in-frame 52 amino acid deletion within the conserved 88 residue CH1 domain of the Crebbp gene. This mutation disrupts the ability of the CREB binding protein to bind transcriptional regulators. On the C57BL/6 congenic backgrounds homozygotes die after birth. Heterozygotes are viable and fertile on the C57BL/6 congenic background. Homozygotes on the C57BL/6 X 129 F1 hybrid background exhibit smaller size, moderate craniofacial anomalies (blunt snout), improved glucose tolerance and insulin sensitivity, as well as repetitive forelimb rubbing (limb grasping) & repetitive grooming behavior, hyperactivity and reduced anxiety. The F1 hybrids are models for Rubinstein-Taybi Syndrome and Autism Spectrum Disorders. RT-PCR confirms the correct splicing of the RNA (that would produce the deletion in the CH1 domain) in mutant MEFs. Expression of the mutant protein is similar to wild type protein when compared between wild type and homozygous mutant MEFs.
A targeting vector containing a loxP site flanked NEO selection cassette was utilized in the construction of this mutant. This selection cassette was inserted upstream of the CH1 domain encoding exons and the in-frame 52 amino acid deletion (amino acids 342-393) within the conserved 88 residue CH1 domain encoding exon. The construct was electroporated into 129P2/OlaHsd derived E14 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase vector to remove the selection cassette. ES cells that had successfully undergone Cre-mediated recombination and no longer retained the cassette were injected into blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were then backcrossed to C57BL/6J for 24 generations, with female heterozygotes backcrossed to wildtype C57BL/6J males at N3. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
|Allele Name||targeted mutation 2, Paul K Brindle|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Crebbp, CREB binding protein|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||Portions of the CH1 domain (amino acids 342-393) was deleted and a neomycin resistance cassette flanked by loxp sites was introduced to the upstream intron. Transient infection of the ES cells with a Cre-expressing vector excised the neomycin cassette. RT-PCR confirmed the deletion in mutant MEFs.|
When maintaining a live colony, heterozygous mice may be bred together, to wildtype siblings, or to C57BL/6J inbred mice (Stock No. 000664). Homozygotes have a perinatal lethal phenotype.
When using the B6.129P2-Crebbptm2Pkb/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #025172 in your Materials and Methods section.