B6;FVB-Tg(Thy1-CAST)12Rnix/J

Stock number: 037192
Product name: hCAST Tg, Thy-1-hCAST line 12

Research areas: Neurobiology Research

Description

hCAST Tg mice express the human CAST (calpastatin) gene under the control of the neuron specific Thy1.1 promoter. hCAST is highly expressed in neuronal tissues including brain, optic nerve, spinal cord, sciatic nerve, and motor neurons (but not astrocytes). This strain may be useful for studying the function of calpain in neurodegenerative disease including Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease, Huntington's disease, FTDP, and Parkinson's disease.

Detailed description

CAST (calpastatin) encodes a calcium dependent calpain inhibitor. Calpains function as calcium-dependent cysteine proteases that are involved in proteolysis of target proteins and the regulation of signal transduction pathways. Depletion of CAST and the resulting increased calpain activity is associated synaptic dysfunction, cytoskeletal disruption, and neurodegeneration in several neurodegenerative diseases including Alzheimer's disease and Amyotrophic Lateral Sclerosis (ALS).

hCAST Tg mice express the human CAST (calpastatin) gene under the control of the neuron specific Thy1.1 promoter. hCAST is highly expressed in neuronal tissues including brain, optic nerve, spinal cord, sciatic nerve, and motor neurons (but not astrocytes). hCAST is not detected in peripheral tissues (kidney, liver, heart, skeletal muscle). Mice homozygous for the transgene are viable and fertile with no obvious phenotype. hCAST transgenic mice injected with kainic acid (KA) to induce neurodegeneration do not develop seizures, exhibit reduced levels of Cal II immunoreactivity, α-spectrin cleavage products, and caspase 3 cleaved tau. In addition, tau phosphorylation is significantly blocked in hCAST mice as compared to controls.

When combined with the ALS mouse model carrying Tg(SOD1*G93A)^dl1Gur (B6.Cg-Tg(SOD1*G93A)^dl1Gur/J Stock No. 002299), overexpression of hCAST in double mutant progeny delays disease onset by lowering calpain activity, inhibiting breakdown of cytoskeletal proteins, reducing motor axon loss, and inhibiting production of neurotoxic tau. This strain may be useful for studying the function of calpain in neurodegenerative disease including ALS, Alzheimer's, Huntington's, FTDP, and Parkinson's.

Development

The hCAST transgenic construct contains a mouse Thy1.1 (thymocyte differentiation antigen) promoter directing expression of the human CAST (calpastatin) coding sequence. The linearized construct was microinjected into the pronuclei of fertilized FVB/NJ mice. Founder line 12 expressed the highest amount of CAST protein (17 fold higher than controls). Line 12 was backcrossed to C57BL/6J for 10 generations by the donating laboratory (see SNP note below). 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).

In 2022, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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. Nine of the 43 markers throughout the genome were segregating with FVB, suggesting an incomplete backcross.

Allele

Symbol: Tg(Thy1-CAST)12Rnix
Name: transgene insertion 12, Ralph A Nixon
MGI accession ID: MGI:7311562
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: hCAST Tg
Marker symbol: Tg(Thy1-CAST)12Rnix
Marker name: transgene insertion 12, Ralph A Nixon
Chromosome: UN
Strain of origin: FVB/NJ
Molecular note: The transgenic construct contains a mouse Thy1.1 (thymocyte differentiation antigen) promoter directing expression the human CAST (calpastatin) coding sequence. Founder line 12 expressed the highest amount of CAST protein (17 fold higher than controls).