Functional Characterization of pkr Gene Products Expressed in Cells from Mice with a Targeted Deletion of the N terminus or C terminus Domain of PKR
Bibliographic record
Abstract
The interferon-inducible double-stranded RNA (dsRNA)-activated protein kinase, PKR, plays an important role in messenger (m) RNA translation by phosphorylating the alpha subunit of eukaryotic initiation factor 2. Through this capacity PKR is thought to be a mediator of the antiviral and antiproliferative actions of interferon. In addition to translational function, PKR has been implicated in many signaling pathways to gene transcription by modulating the activities of a number of transcription factors, including NF-kappa B and STATs. However, experiments with two different PKR knockout (PKR(-/-)) mouse models have failed to verify many of the biological functions attributed to PKR. In addition, results with cells from the two PKR(-/-) mice have been contradictory and confusing. Here, we show that the first PKR(-/-) mouse with deletion of exons 2 and 3, corresponding to the N terminus domain of PKR (N-PKR(-/-)), expresses a truncated protein, resulting from the translation of the exon-skipped mouse PKR (ES-mPKR) mRNA. The ES-mPKR protein is defective in dsRNA binding but remains catalytically active both in vitro and in vivo. Furthermore, we show that the second PKR(-/-) mouse with a targeted deletion of exon 12, which corresponds to the C terminus of the molecule (C-PKR(-/-)), expresses a truncated mPKR produced by alternative splicing of exon 12. Although the spliced form of mPKR (SF-mPKR) is catalytically inactive, it retains the dsRNA-binding properties of the wild type mPKR. Reverse transcription-PCRs demonstrate that SF-mPKR mRNA is expressed in several normal mouse tissues, and appears to be under developmental control during embryogenesis. Our data demonstrate that both PKR(-/-) models are incomplete knockouts, and expression of the PKR variants may account, at least in part, for the significant signaling differences between cells from the two PKR(-/-) mice.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".