Viral proteins and virus-like particles of the LTR5_Hs endogenous retrovirus in human primordial germ cell-like cells
Bibliographic record
Abstract
ABSTRACT The hominoid-specific endogenous retrovirus LTR5_Hs is transcriptionally activated in human primordial germ cell-like cells (hPGCLCs), a pluripotent stem cell-derived cell culture model of PGCs. Here, taking the unique advantage of our novel cell culture method to obtain large amounts of pure hPGCLCs, we performed proteomics profiling of hPGCLCs and detected various viral proteins produced from the LTR5_Hs RNA via ribosomal frameshifting. We also present transmission electron microscopy images of 100-nm diameter virus-like particles (VLPs) assembled at the surface of hPGCLCs. Compared to hPGCLCs, expression of LTR5_Hs RNA is far weaker in human seminomas, the germ cell tumors resembling PGCs. Re-analysis of published single cell RNA-seq data of human embryos revealed strong activation of LTR5_Hs in migrating PGCs but suppressed in PGCs upon they reach the gonadal anlagen. In the microfluidics-supported polarized embryoids mimicking peri-implantation stages of human embryos, LTR5_Hs RNA was detected by RNA in situ hybridization in NANOG + /TFAP2C + /SOX17 + cells resembling freshly emerged PGCs. These results support that human germ cells produce LTR5_Hs proteins and VLPs during their earliest stages of normal development until their settlement in the gonadal anlagen. SUMMARY STATEMENT The hominoid-specific endogenous retrovirus LTR5_Hs is activated in a cell culture model resembling early-stage human primordial germ cells, producing not only viral RNA but also retrovirus proteins and virus-like particles.
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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) | 0.000 | 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) | 0.001 | 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 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".