B6;C3-Tg(NEFH-tTA)8Vle/J

Stock number: 025397
Product name: NEFH-tTA line 8
Research areas: Neurobiology Research, Research Tools

Description

NEFH-tTA transgenic line 8 has the human neurofilament heavy polypeptide promoter directing tetracycline-controlled transactivator protein (tTA) expression primarily to large-caliber axons of the brain and spinal cord. These mice are a "Tet-Off" tool useful for studying neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), as well as other neurobiological, neurodevelopmental, neuromuscular and aging studies involving the neurons of the brain and spinal cord.

Detailed description

NEFH-tTA transgenic mice have the human neurofilament heavy polypeptide (NEFH) promoter directing expression of tetracycline-controlled transactivator protein (tTA) to neurons with large-caliber axons of the brain and spinal cord. NEFH-tTA transgenic line 8 has its highest tTA expression in developmental late stage of the cortex, cerebellum and hippocampus, with expression also observed in olfactory bulb and in the rest of the brain. When mated to a second strain carrying a gene of interest under the regulatory control of a tetracycline-responsive promoter element (TRE; tetO), expression of the target gene can be blocked by administration of the tetracycline analog, doxycycline (dox).

For example, NEFH-tTA mice are useful in studying brain disorders such as amyotrophic lateral sclerosis (ALS) / frontotemporal lobar degeneration (FTLD) when used in conjunction with tetO-hTDP-43 transgenic mice. Specifically, the regulatable NLS (rNLS8) double transgenic line is created by breeding NEFH-tTA line 8 with TRE-promoter-driven cytoplasmic-insoluble human TDP-43ΔNLS transgenic mice (tetO-hTDP-43-ΔNLS line 4 ; Stock No. 014650). On a mixed C57BL/6J x C3HeJ F1 genetic background, rNLS8 mice exhibit widespread, high levels of hTDP-43ΔNLS expression in neurons of both the brain and spinal cord (SC) as early as 1 week off-dox. The brain/SC combination of hTDP-43-ΔNLS expression accounts for the spinal motor neuron loss and muscle denervation; resulting in a rapid, robust and progressive neurodegenerative ALS-like phenotype (including motor deficits, denervation of neuromuscular junctions, motor neuron loss and premature death at ~8-20 weeks). Upon administration of dox, the observed TDP-43 pathology and functional deficits were found to be largely reversible, even after neurodegeneration was underway (~8 weeks of hTDP-43-ΔNLS expression). Breeding NEFH-tTA with TRE-promoter-driven human TDP-43 wildtype transgenic mice (tetO-hTDP-43-WT line 12 ; Stock No. 016841) provides a regulatable control double transgenic line that exhibits broad nuclear hTDP-43-WT expression in the brain and spinal cord, without the formation of cytoplasmic TDP-43 pathology.
In addition, breeding NEFH-tTA mice to tetO-hα-syn-A53T line 33 (Stock No. 016976) allows studying Parkinson's disease.

Importantly, the donating investigator reports that this human NEFH promoter drives slightly higher levels of tTA expression in the cortex compared to their experiences with the mouse Camk2a promoter used in Camk2a-tTA mice (greater than ~10-fold higher than endogenous NEFH versus ~8-fold higher than endogenous CAMK2A). In addition, the human NEFH promoter directs tTA expression in spinal cord (whereas the mouse Camk2a promoter did not).

Hemizygous NEFH-tTA mice are viable and fertile, have normal lifespan out to latest date tested (18 months) and have no observed abnormalities. Homozygous mice are viable. The donating investigator reports that breeding homozyotes to wildtype animals results in hemizygous offspring, but breeding homozygous mice together did not generate any offspring.

Development

NEFH-tTA transgenic mice were designed in the laboratory of Dr. Virginia Man-Yee Lee (University of Pennsylvania) to have ~18 kbp of the human neurofilament heavy polypeptide promoter (NEFH; from BAC RP11-91J21) upstream of the tetracycline-regulated transactivator gene (tTA or "Tet-Off"), all followed by a polyA signal. The NEFH-tTA transgene was injected into the pronucleus of fertilized eggs from (C57BL/6J x C3HeJ)F1 matings (Stock No. 100010). Founder animals were bred to B6C3F1/Crl for germline transmission, and founder line 8 was established. NEFH-tTA transgenic line 8 was then maintained by breeding hemizygous males with B6C3F1/Crl females for at least three generations prior to sending to The Jackson Laboratory Repository in 2013. Upon arrival, sperm was cryopreserved. To establish our living colony, an aliquot of the frozen sperm was used to fertilize oocytes from B6C3F1/J females (Stock No. 100010).

In September 2015, the donating investigator reported that the transgene insertion site(s) and copy number were not known, although multiple copies are likely as the expression level is 9-10-fold greater than endogenous levels.
In 2020, McMillan et al. 2020 Acta Neuropathol Commun 8:200 reported that mice obtained from The Jackson Laboratory Stock No. 025397 have the NEFH-tTA transgene inserted into chromosome 12 [Chr12:6,917,892-6,917,912] without any disruption of gene regions, but did not indicate any transgene copy number information.

Allele

Symbol: Tg(NEFH-tTA)8Vle
Name: transgene insertion 8, Virginia M-Y Lee
MGI accession ID: MGI:5693898
Generation method: Transgenic
Attributes: Transactivator
Marker symbol: Tg(NEFH-tTA)8Vle
Marker name: transgene insertion 8, Virginia M-Y Lee
Chromosome: 12
Strain of origin: (C57BL/6J x C3H/HeJ)F1
Expressed genes: tTA,tetracycline-controlled transactivator,E. coli
Site of expression: tTA is expressed in developmental late stage of the cortex, cerebellum and hippocampus, with expression also observed in olfactory bulb and in the rest of the brain.
Molecular note: The construct consists of ~18 kbp of the human neurofilament heavy polypeptide promoter (NEFH; from BAC RP11-91J21) upstream of the tetracycline-regulated transactivator gene (tTA or "Tet-Off"), followed by a polyA signal. Founder line 8 has its highest tTA expression in developmental late stage of the cortex, cerebellum and hippocampus, with expression also observed in olfactory bulb and in the rest of the brain.