B6.Cg-Mapt^tm1(EGFP)Klt Tg(MAPT)8cPdav/J

Stock number: 005491
Product name: htau
Research areas: Neurobiology Research, Research Tools

Description

htau mice lack endogenous microtubule-associated protein tau (Mapt) gene expression, and express all six isoforms (including both 3R and 4R forms) of human MAPT. These mutant mice may be useful in studies examining the relationship between human MAPT and Alzheimer's disease pathogenesis

Detailed description

htau mice have an EGFP sequence and a neo cassette disrupting exon 1 of the microtubule-associated protein tau (Mapt) gene. In addition, it contains a transgene encoding the human MAPT gene.

The MAPT gene encodes a protein that is involved in regulating microtubule assembly and stability, as well as neuron axonal polarity. Alternative splicing of the gene generates several isoforms of different lengths. Mutations in this gene have been associated with frontotemporal dementia with Parkinsonism, progressive supranuclear palsy, Pick disease, Parkinson's disease, and Alzheimer's disease.

In these htau mice, all six isoforms (including both 3R and 4R forms) of human MAPT are expressed, while no endogenous mouse MAPT is detected. EGFP is detectable by immunohistochemistry and western blot in brain lysates. Hyperphosphorylated MAPT is detected by EGFP fluorescence in cell bodies and dendrites by three months of age. Paired helical filaments of aggregated insoluble MAPT can be isolated from brain tissue as early as two months of age [Phillips et al. PLoS One May 2011].

Mice that are homozygous for the targeted allele and hemizygous for the transgene are viable and fertile. The donating investigator reports that mice homozygous for the transgenic insert have never been observed and that such mice are presumed to be embryonic lethal.

EGFP is not detectable by direct fluorescence.

Development

Tau KO mice contain a targeted mutation that inserts an enhanced green fluorescent protein (EGFP) coding sequence and a neomycin resistance (neo) cassette into the first Mapt exon, disrupting expression of the Mapt gene and producing a cytoplasmic EGFP protein fused to the first 31 MAPT amino acids (see Stock No. 004779). The construct was electroporated into 129S4/SvJae-derived J1 embryonic stem (ES) cells and correctly targeted ES cells were injected into recipient blastocysts from C57BL/6J females.

A transgene was also created which consisted of a PAC insert of 200-250 kb that included the coding sequence, intronic regions and regulatory elements of the human MAPT gene. The transgenic allele was generated in embryos derived from a cross between Swiss Webster females and B6D2F1 males. Mice, from founder line 8C, were bred to Tau KO mice, and resulting mice, containing both alleles, were crossed to C57BL/6 mice for nine generations by the donating investigator. Upon arrival at The Jackson Laboratory, 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: Tg(MAPT)8cPdav
Name: transgene insertion 8c, Peter Davies
MGI accession ID: MGI:3057129
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Marker symbol: Tg(MAPT)8cPdav
Marker name: transgene insertion 8c, Peter Davies
Chromosome: UN
Strain of origin: Swiss Webster x (C57BL/6 x DBA)F1
Expressed genes: MAPT,microtubule associated protein tau,human
Site of expression: Neurons: EGFP signal observed at 9.0 dpc (days post-coitum) in the trilgeminal ganglion. At 10.75 dpc. EGFP was seen throughout the developing nervous system.
Molecular note: The transgene contains the coding sequence, intronic regions, and regulatory elements of the human microtubule-associated protein tau (MAPT) gene.
General note: Mice that are homozygous for the Mapt^tm1(GFP)Klt allele and hemizygous for the transgene are viable and fertile. Although no endogenous mouse MAPT is detected, all six isoforms (including both 3R and 4R forms) of human MAPT are expressed. Hyperphosphorylated MAPT is detected in cell bodies and dendrites by 3 months of age. Paired helical filaments of aggregated insoluble MAPT can be isolated from brain tissue as early as 2 months of age.

Allele

Symbol: Mapt^tm1(EGFP)Klt
Name: targeted mutation 1, Kerry Lee Tucker
MGI accession ID: MGI:2670768
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Mapt
Marker name: microtubule-associated protein tau
Chromosome: 11
Strain of origin: 129S4/SvJae
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: GFP signal is detected beginning a embryonic day 9 in the trigeminal ganglion and throughout the developing central nervous system by embryonic day 10.75. GFP expression persists in adults and closely resembles the expression of neuron specific beta-tubulin III.
Molecular note: Exon 1 was disrupted by the insertion of a cassette encoding the EGFP fluorescent marker gene and a neomycin resistance gene. Fusion protein including EGFP was detected by Western blot analysis of homozygous mutant brain lysates. Fluorescent illumination indicated that expression of the reporter gene was similar to that of the endogenous gene.