B6.Cg-Tg(Thy1-UBQLN2*P497S)3Mont/J

Stock number: 029968
Product name: Thy1.2-UBQLN2*P497S line 3 (P497S_3)
Research areas: Neurobiology Research, Research Tools

Description

Thy1.2-UBQLN2*P497S line 3 has the neuronal-specific Thy1.2 promoter directing expression of a cDNA encoding the human ubiquilin 2 P497S mutant protein that is associated with dominant inheritance of amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD).

The donating investigator also made available their other mutant-expressing transgenic strain (Thy1.2-UBQLN2*P506T line 6 ; Stock No. 029969) as well as their wildtype control strain (Thy1.2-UBQLN2 line WT-356 ; Stock No. 029970).



See Detailed Description for information on phenotype differences of these mice on different genetic backgrounds.

Detailed description

Ubiquilin 2 (UBQLN2) is a protein that functions in protein folding and degradation pathways. It assists in protein folding by binding chaperones and facilitates disposal of misfolded proteins through proteasome and autophagy pathways. Missense mutations in human UBQLN2 (hUBQLN2) are linked to dominant inheritance of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). Patients carrying ALS/FTD mutations in UBQLN2 display accumulation of ubiquinated proteins (inclusions) in the lower motor neurons and upper corticospinal motor neurons.

Dr. Mervyn J. Monteiro made several transgenic mouse lines with the Thy1.2 promoter sequences (driving expression only in neurons throughout the central and peripheral nervous system) upstream of a cDNA encoding a human UBQLN2 mutant protein (P497S or P506T) or a full-length wildtype human UBQLN2. The following mouse lines are available at The Jackson Laboratory: Thy1.2-UBQLN2*P497S line 3 on a C57BL/6J-congenic background (029968 ; >99% C57BL/6J), Thy1.2-UBQLN2*P506T line 6 on a C57BL/6J;C3H genetic background (Stock No. 029969 ; ~87.5% C57BL/6J) and the Thy1.2-UBQLN2 line WT-356 control on a C57BL/6J-congenic background (Stock No. 029970 ; >99% C57BL/6J).

The phenotype originally published on the C57BL/6J;C3H genetic background (75% or more C57BL/6J) for all three transgenic lines is described in the primary publication summary paragraph further below. Of note, the donating investigator reports that the Thy1.2-UBQLN2*P497S line 3 phenotype became less severe when backcrossed onto C57BL/6J (see supporting data in next paragraph), whereas the Thy1.2-UBQLN2*P506T line 6 phenotype became even more severe with backcrossing onto C57BL/6J.

In 2020, The Jackson Laboratory assessment of frailty, rotorod and grip strength confirms the donating investigators report that the Thy1.2-UBQLN2*P497S line 3 phenotype is less severe on the C57BL/6J genetic background (>99% C57BL/6J) compared to the mixed C57BL/6J;C3H genetic background (~75% on C57BL/6J). In support of this, transgenic expression of hUBQLN2 protein (western blot of brain and spinal cord) was reduced on the C57BL/6J genetic background compared to the mixed C57BL/6J;C3H genetic background values in the original publication. [View Data]

The primary publication (Le et al. 2016 Proc Natl Acad Sci U S A 113:E7580) describes several transgene carrier lines on a C57BL/6J;C3H genetic background (75% or more C57BL/6J): Thy1.2-UBQLN2*P497S line 3 (having ~5 transgene copies), Thy1.2-UBQLN2*P506T line 6 (having ~2 transgene copies) and Thy1.2-UBQLN2 line WT-356 (having ~1.5-3.5 transgene copies). All three lines had similar hUBQLN2 expression pattern and levels. Transgenic hUBQLN2 protein expression is observed in the brainstem, cortex, hippocampus and striatum, with lower expression in the cerebellum. Expression in peripheral neurons has not been evaluated to date (March 2017). Spinal cord lysates from 1 month-old transgenic animals show hUBQLN2 expression levels ~70-80% that of endogenous mouse levels.
The two mutant hUBQLN2 expressing lines display hallmark characteristics of human ALS-FTD, including cognitive deficits, motor neuron disease, TDP-43 pathology and shortened lifespan. Neuropathologic analysis of end-stage disease mice reveals ubiquitinated inclusion accumulation in brain and spinal cord, astrocytosis, reduction in number of hippocampal neurons, and reduced TDP-43 staining in the nucleus with concomitant formation of ubiquitin+ inclusions in the cytoplasm of spinal motor neurons. In addition, they display denervation muscle atrophy and age-dependent motor neuron loss that correlates with a reduction in the number of large-caliber axons. Thy1.2-UBQLN2*P497S line 3 disease onset was ~80 days, with lethality starting ~280 days, 50% death by ~350 days and 100% death by ~450 days. Thy1.2-UBQLN2*P506T line 6 disease onset was ~40 days, with lethality starting ~200 days, 50% death by ~250 days and 100% death by ~450 days. In addition to these differences in survival curves, the two mutant hUBQLN2 expressing lines also differ in that Thy1.2-UBQLN2*P497S line 3 contained more UBQLN2+ inclusions in brain and spinal cord.
The control strain, Thy1.2-UBQLN2 line WT-356, expresses full-length wildtype hUBQLN2. These mice have normal lifespan and do not display motor neuron disease. However, their overexpression of hUBQLN2 results in some neuron loss (upper motor neurons and dentate gyrus neurons) and altered axonal caliber profile (increase in small-caliber axons and a general shift of the large-caliber axons to slightly smaller axons).

C57BL/6J-congenic Thy1.2-UBQLN2*P497S line 3 hemizygous mice are viable and fertile. The phenotype of homozygous mice has not been characterized to date (March 2017).

Development

Thy1.2-UBQLN2*P497S transgenic line 3 was created by Dr. Mervyn J. Monteiro (University of Maryland). The transgene was designed to have the modified ~6.5 kbp mouse Thy1.2 promoter (Thy1 sequences extending from the promoter to the intron following exon 4, excluding exon 3 and its flanking introns) followed by a cDNA sequence encoding the human ubiquilin 2 protein harboring a proline-to-serine missense mutation at amino acid 497 (UBQLN2*P497S). UBQLN2 missense mutations (including this one) are linked to dominant inheritance of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). The ~8.5 kbp transgene was injected into fertilized B6C3/C57BL/6J hybrid eggs, and transgenic founders were bred with C57BL/6J mice for germline expression. Founder line P497S_3 was found to have ~5 copies of the transgene, and was further characterized. The donating investigator reports that the Thy1.2-UBQLN2*P497S line 3 colony was backcrossed to C57BL/6J for at least eight generations, and then males with black coat color were sent to The Jackson Laboratory Repository in 2017. 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).
Of note, the donating investigator reports that, at least once during backcrossing, a hemizygous female was bred to a C57BL/6J inbred male (thus the Y chromosome of the congenic strain is of C57BL/6J origin). In addition, the transgene insertion site(s) are not known to date (March 2017).

Allele

Symbol: Tg(Thy1-UBQLN2*P497S)3Mont
Name: transgene insertion 3, Mervyn Monteiro
MGI accession ID: MGI:5829037
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: P497S
Marker symbol: Tg(Thy1-UBQLN2*P497S)3Mont
Marker name: transgene insertion 3, Mervyn Monteiro
Chromosome: UN
Strain of origin: C3H or C57BL/6 or C57BL/6J
Expressed genes: UBQLN2,ubiquilin 2,human
Molecular note: The transgene was designed to have the modified ~6.5 kbp mouse Thy1.2 promoter (Thy1 sequences extending from the promoter to the intron following exon 4, excluding exon 3 and its flanking introns) followed by a cDNA sequence encoding the human ubiquilin 2 protein harboring a proline-to-serine missense mutation at amino acid 497. UBQLN2 missense mutations (including this one) are linked to dominant inheritance of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). Founder line 3 was found to have 5 copies of the transgene.
General note: The transgenic construct was injected into fertilized B6C3/C57BL/6J hybrid eggs. (J239510)