Exon 9 of the mouse Ep300 gene is flanked by loxP sites in this conditional mutant strain. Cre excision of the floxed region creates a knockout allele, useful in studies of transcriptional regulation.
Paul K. Brindle, St. Jude Children's Research Hospital
Ep300 (E1A binding protein p300) is a histone acetylase that is required for normal development. It interacts with a significant percentage of mammalian transcriptional regulatory proteins, thus influences a broad range of physiological pathways.
Exon 9 of the mouse Ep300 gene is flanked by loxP sites in this conditional mutant strain. Homozygotes are viable and fertile, and appear normal. Excision of the floxed region by cre recombinase results in a knockout allele.
Knockouts created through crosses with thymocyte-specific Lck-cre mice show a decrease in the number of CD4+ CD8+ double-positive thymocytes, but an increase in the percentage of CD8+ single-positive thymocytes. Mice with high deletion frequencies are deficient for full-length and truncated protein, as measured by Western blot.
A loxP site was introduced to intron 8 and an FRT-neomycin-chloramphenicol-thymidine kinase-FRT cassette followed by a loxP site was placed in intron 9 through homologous recombination in 129P2/OlaHsd-derived E14 embryonic stem (ES) cells. Transient expression of Flp recombinase in the ES cells excised the FRT'ed drug selection cassette, leaving exon 9 flanked by loxP sites. Resultant chimeric mice were crossed with C57BL/6J animals, then to 129P2/Ola for 3 generations. Fertility/productivity issues precipitated 14 generations of backcrossing to 129S2/SvPasCrl by the donating laboratory.
|Allele Name||targeted mutation 2, Paul K Brindle|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Ep300, E1A binding protein p300|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||Exon 9 is flanked by LoxP sites (in same orientation). There also is one Frt site 3' of exon 9 left from removal of selection cassette. Absence of transcription and translation products was confirmed by QRT-PCR, immunohistochemistry, and Western blot analysis.|
Heterozygotes and homozygotes are viable and fertile.
When using the p300 flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #025526 in your Materials and Methods section.