An enhanced Q175 knock-in mouse model of Huntington disease with higher mutant huntingtin levels and accelerated disease phenotypes
Bibliographic record
Abstract
Huntington disease (HD) model mice with heterozygous knock-in (KI) of an expanded CAG tract in exon 1 of the mouse huntingtin (Htt) gene homolog genetically recapitulate the mutation that causes HD, and might be favoured for preclinical studies. However, historically these mice have failed to phenotypically recapitulate the human disease. Thus, homozygous KI mice, which lack wildtype Htt, and are much less relevant to human HD, have been used. The zQ175 model was the first KI mouse to exhibit significant HD-like phenotypes when heterozygous. In an effort to exacerbate HD-like phenotypes and enhance preclinical utility, we have backcrossed zQ175 mice to FVB/N, a strain highly susceptible to neurodegeneration. These Q175F mice display significant HD-like phenotypes along with sudden early death from fatal seizures. The zQ175 KI allele retains a floxed neomycin resistance cassette upstream of the Htt gene locus and produces dramatically reduced mutant Htt as compared to the endogenous wildtype Htt allele. By intercrossing with mice expressing cre in germ line cells, we have excised the neo cassette from Q175F mice generating a new line, Q175FΔneo (Q175FDN). Removal of the neo cassette resulted in a ∼2 fold increase in mutant Htt and rescue of fatal seizures, indicating that the early death phenotype of Q175F mice is caused by Htt deficiency rather than by mutant Htt. Additionally, Q175FDN mice exhibit earlier onset and a greater variety and severity of HD-like phenotypes than Q175F mice or any previously reported KI HD mouse model, making them valuable for preclinical studies.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".