The Ino80 Floxed (Ino80fl) allele has loxP sites flanking exons 2-4 of the Ino80 gene. Removal of the floxed sequence creates a null allele. These mice may be useful in studying the function of the Ino80 chromatin remodeling complex in regulation of DNA repair, DNA replication and transcription.
Joseph W Landry, Virginia Commonwealth University, School of Medicine
The Ino80 Floxed (Ino80fl) allele has loxP sites flanking exons 2-4 of the Ino80 gene.
The Ino80 chromatin remodeling complex is involved in the regulation of DNA repair, DNA replication and transcription. Specifically, Ino80 occupies the Bmp4 promoter to prevent over-expression during differentiation.
Mice homozygous for the Ino80 Floxed allele are viable and fertile with no reported abnormalities.
When bred to mice that express Cre recombinase, the resulting offspring may be useful in generating a tissue-specific Ino80 knockout.
For example, when bred to germline Cre-expressing mice (Stock No. 006054), the resulting Ino80 global knockout (Ino80 KO) homozygotes die in utero; knockout embryos implant but fail to develop beyond the egg cylinder stage. In addition, Ino80 KO embryonic stem cells are viable and maintain alkaline phosphatase activity suggesting an ability to maintain pluripotency, but fail to differentiate as either embryoid bodies or teratomas.
The Ino80 Floxed mice (Ino80fl) were created by Dr. Joseph W. Landry (Virginia Commonwealth University). First, a targeting vector was designed to have a loxP site upstream of exon 2, and a frt-flanked neo cassette followed by a second loxP site just downstream of exon 4 of the INO80 homolog (S. cerevisiae) gene (Ino80) on chromosome 2.
The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl+ derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeras were bred with C57BL/6J mice to establish the Ino80 Floxed-Neo colony.
Offspring were bred with Flp-transgenic mice (on a C57BL/6 background; Stock No. 011065) for germline deletion of the neo cassette.
The resulting Ino80 Floxed mice (Ino80fl) were bred with C57BL/6J wildtype mice for at least five generations (and the Flp-expressing transgene was removed) prior to sending males to The Jackson Laboratory Repository in 2013 (see SNP note below).
Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm is used to fertilize C57BL/6J oocytes (Stock No. 000664).
Of note, it is not known if the Y chromosome has been fixed to the C57BL/6J background during backcrossing.
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 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. Two the 27 markers throughout the genome were still segregating with 129. Also, 2 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.
|Allele Name||targeted mutation 1.1, Joseph Landry|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Allele Synonym(s)||Ino80 Floxed; Ino80fl|
|Gene Symbol and Name||Ino80, INO80 complex subunit|
|Strain of Origin||(129X1/SvJ x 129S1/Sv)F1-Kitl+|
|Molecular Note||The targeting vector is designed to have a loxP site upstream of exon 2, and an FRT-flanked neo cassette followed by a second loxP site just downstream of exon 4. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exons 2 through 4 floxed.|
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 Ino80 Floxed (Ino80fl) mouse strain in a publication, please cite the originating article(s) and include JAX stock #027920 in your Materials and Methods section.