In this CBPKIX mutant strain the interaction between the phosphorylated CREB and CREB-binding protein is blocked. This strain may be useful in studies of the role of the CREB-binding protein histone acetyltransferase and hematopoiesis.
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 CBPKIX mice carry triple point mutations (Tyr650Ala, Ala654Gln, and Tyr658Ala ) in the KIX domain encoding exon, resulting in the production of a hypomorphic protein that cannot bind CREB or c-Myb via this domain. The interaction between the phosphorylated CREB and CREB-binding protein is blocked in these mutants.
Although homozygotes are viable, approximately 40% of homozygotes die before weaning. Surviving homozygotes are fertile. Homozygotes are smaller than wildtype controls, have slightly fewer number of thymocytes, impaired long term memory for contextual fear and for novel object recognition. Protein stability and expression are unaltered as detected by Western Blot analysis of nuclear extracts from brain tissue of homozygous animals.
A targeting vector containing a floxed NEO cassette was utilized in the construction of this mutant. This selection cassette was inserted upstream of the exon encoding the KIX and the Tyr650Ala, Ala654Gln, and Tyr658Ala point mutations were introduced into the KIX 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 29 generations, with female heterozygotes backcrossed to wildtype C57BL/6J males at N5 and N8. 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 1, Paul K Brindle|
|Allele Type||Targeted (Not Specified)|
|Gene Symbol and Name||Crebbp, CREB binding protein|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||A floxed neomycin selection cassette was inserted upstream of the exon encoding the KIX domain and the KIX containing exon itself was mutated so that the tyrosine at amino acid residue 650 became alanine, the alanine at residue 654 became glutamine and the tyrosine at residue 658 became alanine (Y650A, A654Q and Y658A). Transient cre expression then excised the selection cassette. Expression and stability of the mutated product were normal.|
When maintaining a live colony, heterozygous mice may be bred together, to wildtype siblings, or to C57BL/6J inbred mice (Stock No. 000664). Almost half (40%) of homozygotes die by weaning age.
When using the B6.129P2-Crebbptm1Pkb/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #025171 in your Materials and Methods section.