STOCK Ascl1^tm2.1Fgu/JejoJ

Stock number: 037042
Product name: Ascl1^flox
Research areas: Cell Biology Research, Neurobiology Research, Research Tools

Description

Ascl1^flox/flox mice have loxP sites flanking the entire coding region of the Ascl1 gene and also contain a Venus fluorescent sequence downstream of the floxed region. This mutant mouse strain may be useful in studying distinct neuronal cell populations, neuronal turnover, and neuronal migration. The donating investigator reports that the level of expression of the Venus reporter gene is below detection via direct fluorescence and immunohisotchemistry.

Detailed description

Ascl1^flox/flox mice have loxP sites flanking the entire coding region of the achaete-scute family bHLH transcription factor 1 (Ascl1) gene and also contain a Venus fluorescent sequence downstream of the floxed region. Ascl1 is a transcription factor expressed in neural progenitor cells in the embryo and the adult brain, including progenitors to subsets of neurons throughout the central nervous system (CNS) and the peripheral nervous system (PNS), and in developing neuroendocrine cells in lung, pituitary, thyroid, prostate, and adrenal. Mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have the entire coding region removed in the Cre-expressing tissues of the offspring, leaving the Venus sequence intact. The donating investigator reports that the level of expression of the Venus reporter gene is below detection via direct fluorescence and immunohisotchemistry.

Of note, Stock No. 012881 contains a GFP reporter that knocks out Ascl1 expression.

Development

The Ascl1^flox targeting vector was designed to insert a loxP site upstream of the coding region of the achaete-scute family bHLH transcription factor 1 (Ascl1) gene. A second loxP site followed by a Venus fluorescence sequence and a frt-flanked neomycin resistance cassette were inserted downstream of the 3’ UTR. 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 blastocysts. The original reference stated that the frt sites surrounding the neo cassette were non-functional. After further attempts, the neo cassette was successfully removed by breeding mice with CAG-Flp-expressing mice. Resulting offspring were crossed to remove the Flp expressing allele, and mice were subsequently bred to ICR outbred mice to maintain the colony. The donating laboratory also crossed these mice to mice containing the Ai14 allele (Stock No. 007914) and removed that mutation prior to shipping mice to The Jackson Laboratory. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Ascl1^tm2.1Fgu
Name: targeted mutation 2.1, Francois Guillemot
MGI accession ID: MGI:6388406
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Ascl1
Marker name: achaete-scute family bHLH transcription factor 1
Chromosome: 10
Strain of origin: Not Specified
Molecular note: A loxP site was inserted upstream of the coding sequence. A Venus gene with a 5' loxP site and an FRT-flanked neo cassette were inserted downstream of the 3' UTR. Flp-mediated recombination removed the selection cassette.