B6.Cg-Tg(Thy1-UBQLN2)356Mont/J

Stock number: 029970
Product name: Thy1.2-UBQLN2 line WT-356 (WT 356)
Research areas: Neurobiology Research, Research Tools

Description

Thy1.2-UBQLN2 line WT-356 has the neuronal-specific Thy1.2 promoter directing expression of a cDNA encoding the full-length, wildtype human ubiquilin 2 protein. Missense mutations in UBQLN2 are associated with dominant inheritance of amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD).

This is a control strain for the two transgenic mouse lines with mutant UBQLN2 expression: Thy1.2-UBQLN2*P497S line 3 (Stock No. 029968) and Thy1.2-UBQLN2*P506T line 6 (Stock No. 029969).



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 paragraph below. Of note, the donating investigator reports that the Thy1.2-UBQLN2*P497S line 3 phenotype became less severe when backcrossed onto C57BL/6J, whereas the Thy1.2-UBQLN2*P506T line 6 phenotype became even more severe with backcrossing onto C57BL/6J.

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 line WT-356 hemizygous mice are viable and fertile. The phenotype of homozygous mice has not been characterized to date (March 2017).

Development

Thy1.2-UBQLN2 transgenic line WT-356 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 full-length, wildtype human ubiquilin 2 protein. UBQLN2 missense mutations are linked to dominant inheritance of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). The ~8.5 kbp transgene was injected into fertilized SJL/C57BL/6J hybrid eggs, and transgenic founders were bred with C57BL/6J mice for germline expression. Founder line WT-356 was found to have ~1.5-3.5 copies of the transgene, and was further characterized. The donating investigator reports that the Thy1.2-UBQLN2 line WT-356 colony was backcrossed to C57BL/6J for at least six generations prior to sending males with black coat color 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)356Mont
Name: transgene insertion 356, Mervyn Monteiro
MGI accession ID: MGI:5829042
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: UBQLN2 WT
Marker symbol: Tg(Thy1-UBQLN2)356Mont
Marker name: transgene insertion 356, Mervyn Monteiro
Chromosome: UN
Strain of origin: SJL 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 full-length, wildtype human ubiquilin 2 protein. UBQLN2 missense mutations are linked to dominant inheritance of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD). Founder line 356 was found to have ~1.5-3.5 copies of the transgene.
General note: The transgenic construct was injected into fertilized SJL/C57BL/6J hybrid eggs per the primary investigator.