FVB/NJ-Tg(C9orf72_i3)101Lutzy/J

Stock number: 036633
Product name: Tg(C9orf72_3) line 101
Research areas: Neurobiology Research

Description

Tg(C9orf72_3) line 101 mice have at least 3 tandem copies of the C9orf72_3 transgene, with each copy encoding the human C9orf72 with a hexanucleotide repeat expansion in the intron between the alternatively-spliced non-coding first exons 1a and 1b. Each transgene copy has between 100-750 repeats ([GGGGCC]_100-750). Hemizygous mice exhibit RNA foci and soluble poly(GP) dipeptides in cortex, hippocampus and cerebellum by three months of age. These mice may be useful in applications related to amyotrophic lateral sclerosis and frontotemporal dementia.

Detailed description

The most common genetic mutation associated with human amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide repeat expansion in a non-coding region of the chromosome 9 open reading frame 72 gene (C9orf72). The C9orf72 transgene C9orf72_3 encodes the human C9orf72 gene with a hexanucleotide repeat expansion in the intron between the alternatively-spliced non-coding first exons 1a and 1b.

The Tg(C9orf72_3) line 101 mice (Stock No. 036633) have at least 3 tandem copies of the C9orf72_3 transgene, with each copy harboring 780, 530 and 170 repeats ([GGGGCC]_100-750), as assessed on XBAI southern blot. The repeats are stable, as no contractions or expansions in this line have been noted to date (May 2023).

The donating investigator reports that hemizygous mice from Tg(C9orf72_3) line 101 are viable and fertile, with no phenotype until at least three months of age. By three months of age, hemizygous Tg(C9orf72_3) line 101 animals exhibit RNA foci (formed by hexanucleotide-repeat expansion-containing human C9ORF72 RNAs) in cortex, hippocampus and cerebellum. Soluble poly(GP) dipeptides (resulting from a non-ATG initiated translation of the repeat expansion) can also be detected by immunoassay in the brain of hemizygous Tg(C9orf72_3) line 101 mice at three months of age; however, soluble Poly(GP) abundance decreases in mice older than nine months.

Note, if additional characterization of these Tg(C9orf72_3) line 101 mice is performed, we may modify the strain description accordingly.

The Jackson Laboratory Southern Blot Protocol for this transgene is available here [2019]. Using this protocol, the expected band sizes are ~7.5kb, ~6kb, ~3.9kb.

This transgenic mouse strain was generated as part of a study funded by Target ALS.

Development

The C9orf72_3 transgene was designed by Dr. Cat Lutz (The Jackson Laboratory) and Dr. Robert Baloh (Cedars-Sinai) by first obtaining a bacterial artificial chromosome (BAC) clone derived from fibroblasts of a patient with amyotrophic lateral sclerosis (ALS), carrying the human chromosome 9 open reading frame 72 gene (C9orf72) with a hexanucleotide repeat expansion (GGGGCC) in the intron between the alternatively-spliced non-coding first exons 1a and 1b. Sequence isolated from the BAC included a ~166 kbp sequence (~36 kbp human C9orf72 genomic sequence, with ~110 kbp upstream and ~20 kbp downstream sequences). Upon amplification of different BAC subclones in bacteria, the repeat expansion underwent contraction in some clones. A BAC subclone with a limited contraction to 100-750 GGGGCC repeats was used, non-linearized, for microinjection into FVB/NJ blastocysts. Founder animals were bred to FVB/NJ inbred mice (Stock No. 001800) to establish founder line 552-101. At least 3 copies of the transgene integrated in tandem (segregating together); each copy harboring 780, 530 and 170 GGGGCC repeats, as determined by southern blot. The Tg(C9orf72_3) line 101 colony was maintained on an FVB/NJ background prior to freezing sperm at The Jackson Laboratory Repository. To establish our living colony, an aliquot of the frozen sperm was used to fertilize oocytes from FVB/NJ females.

Allele

Symbol: Tg(C9orf72_i3)101Lutzy
Name: transgene insertion 101, Cathy Lutz
MGI accession ID: MGI:7564002
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Marker symbol: Tg(C9orf72_i3)101Lutzy
Marker name: transgene insertion 101, Cathleen Lutz
Chromosome: UN
Strain of origin: FVB/NJ
Molecular note: The transgenic construct contains a bacterial artificial chromosome (BAC) clone derived from fibroblasts of a patient with amyotrophic lateral sclerosis (ALS), carrying the human chromosome 9 open reading frame 72 gene (C9orf72) with a hexanucleotide repeat expansion (GGGGCC) in the intron between the alternatively-spliced non-coding first exons 1a and 1b. Sequence isolated from the BAC included a ~166 kbp sequence (~36 kbp human C9orf72 genomic sequence, with ~110 kbp upstream and ~20 kbp downstream sequences). Upon amplification of different BAC subclones in bacteria, the repeat expansion underwent contraction in some clones. This BAC subclone is limited to a contraction of 100-750 GGGGCC repeats. At least 3 copies of the transgene integrated in tandem (segregating together); each copy harboring 780, 530 and 170 GGGGCC repeats, as determined by southern blot.