C57BL/6-Ntng1^em1(cre)Kfra/J

Stock number: 040740
Product name: Ntng1-Cre
Research areas: Developmental Biology Research, Mouse/Human Gene Homologs, Neurobiology Research, Research Tools

Description

Ntng1-Cre knock-in/knock-out mice have a Cre recombinase gene inserted into the start codon of the Ntng1 locus, abolishing endogenous Ntng1 expression. When these mice are bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination will result in deletion of the floxed sequences in the Ntng1-expressing cells of the offspring. These mice may be useful when studying early neuronal development.

Detailed description

Ntng1 (netrin G1) codes for a glycosyl-phosphatidylinositol-anchored synaptic adhesion molecule that is mainly expressed in the pre-synaptic membrane. Mutations in this gene have been associated with neurodevelopmental disorders, such as Rett Syndrome. Ntng1-Cre knock-in/knock-out (KI/KO) mice have a Cre recombinase gene inserted into exon 1 of the Ntng1 gene, abolishing endogenous Ntng1 expression. When these Ntng1-Cre KI/KO mice are bred with mice containing loxP-flanked sequence, Cre-mediated recombination will result in deletion of the floxed sequences in the cre-expressing cells of the offspring.

Heterozygous mice are viable and fertile with no overt phenotype. Homozygous mice are also viable and fertile based on observations reported by the donating laboratory. These mice may be useful when studying the role of Netrin G1 early neuronal development and neurodevelopmental disorders.

Development

The Ntng1-Cre knock-in/knock-out (KI/KO) allele was generated using CRISPR-mediated homologous recombination. A single guide RNA (5'-CAGCCCTACCTTTTCGTGTG-3'), targeting the netrin G1 (Ntng1) ATG start site, was used to introduce cre recombinase and polyadenylation signal (polyA) sequences, followed by an FRT-flanked neomycin cassette. An additional 162nt of DNA sequence was also inserted at the start codon. The resulting allele contains cre sequence with an extra 5' end 34 amino acids inserted into the start codon of the Ntng1 gene. The sgRNA, donor plasmid and Cas9 nuclease were introduced into C57BL/6-derived embryonic stem (ES) cells. Correctly targeted ES cell clones were identified by PCR and Southern blot analysis. ES cell clone 2C1 was then used to generate chimeric mice, which were subsequently bred to C57BL/6 mice to confirm germline transmission. The resulting Ntng1-Cre KI/KO mouse line was backcrossed to C57BL/6 mice for multiple generations by the donating laboratory. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish a live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J (Stock No. 000664) oocytes.

Of note, genotyping performed by The Jackson Laboratory (June 2026) confirms neomycin cassette is intact and segregating with targeted mutation.

Allele

Symbol: Ntng1^em1(cre)Kfra
Name: endonuclease-mediated mutation 1, Kevin M Franks
MGI accession ID: MGI:6740547
Generation method: Endonuclease-mediated
Attributes: Recombinase-expressing; Null/Knockout
Synonyms: Ntng1-Cre
Marker symbol: Ntng1
Marker name: netrin G1
Marker synonyms: A930010C08Rik; Lmnt1; NetG1; NetrinG1; RGD1563465
Chromosome: 3
Strain of origin: C57BL/6
Molecular note: Using CRISPR/Cas9 technology, sequences encoding the Cre recombinase followed by the bovine growth hormone polyA sequences were inserted at the start codon ATG of Ntng1 gene.