These floxed mutant mice possess loxP sites flanking exons 1 through 4 of the Msi2 gene. This strain may be useful for generating conditional mutations in applications related to the regulation of hematopoietic stem cells and hematopoiesis.
Christopher J. Lengner, University of Pennsylvania
The Msi2 gene encodes for a RNA binding protein that regulates RNA translation, TGF-beta signaling, and is responsible for maintenance of hematopoietic stem cells. Msi2 has also been implicated in regulation of the intestinal epithelium and intestinal stem cells through regulation of mTORC1 activity.
These mice possess loxP sites flanking exons 1 through 4 of the targeted gene. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exons 1 through 4 deleted in the cre-expressing tissues.
When bred to a strain with inducible Cre recombinase expression in bone marrow and spleen, this mutant mouse strain may be useful in studies of regulation of hematopoietic stem cell number and function.
When bred to a strain with inducible Cre recombinase expression in the intestinal epithelium, this mutant mouse strain may be useful for studying intestinal stem cell activity, regeneration, and tumorigenesis.
A loxP site flanked targeting vector containing PGK-Neo selection cassette was utilized in the construction of this mutant. This selection cassette was inserted downstream of exon 4 of the targeted gene, and another loxP site was inserted upstream of exon 1 (transcriptional start site). This construct was electroporated into (C57BL/6 x 129S4/SvJae)F1 derived v6.5 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase vector to remove the selection cassette. Correctly targeted ES cells in which Cre recombination resulted in exons 1 through 4 being flanked by loxP sites were injected into C57BL/6 blastocysts. The resulting chimeric mice were crossed to C57BL/6 mice. The donating investigator reported that these mice were then backcrossed to C57BL/6 for 5 generations (see SNP note below). During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.
Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
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. Six of the 27 markers throughout the genome were segregating, this suggests an incomplete backcross.
|Allele Name||targeted mutation 1.1, Christopher J Lengner|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Allele Synonym(s)||Msi2f; Msi2flox|
|Gene Symbol and Name||Msi2, musashi RNA-binding protein 2|
|Strain of Origin||(C57BL/6 x 129S4/SvJae)F1|
|Molecular Note||Exons 1 through 4 were floxed. Cre-mediated recombination removed the neomycin resistance cassette inserted into intron 5.|
When maintaining a live colony, these mice can be bred as homozygotes.
When using the Msi2flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #027316 in your Materials and Methods section.