The N Terminus of Autographa californica Multiple Nucleopolyhedrovirus DNA Polymerase Is Required for Efficient Viral DNA Replication and Virus and Occlusion Body Production
Bibliographic record
Abstract
ABSTRACT Autographa californica multiple nucleopolyhedrovirus (AcMNPV) DNA polymerase (DNApol) plays a crucial role in viral DNA synthesis, and the N terminus (residues 1 to 186) is highly conserved in the baculovirus DNApol family. However, the functional role of the N terminus of DNApol has not yet been characterized. Here we report a functional analysis of the AcMNPV DNApol N terminus. We truncated the DNApol N terminus to construct truncation mutants Bac-GFP-PolΔ64, Bac-GFP-PolΔ110, and Bac-GFP-PolΔ186, which lack 64, 110, and 186 N-terminal residues, respectively. Although the truncation mutants rescued viral DNA synthesis and infectious virus production, the level of DNA replication decreased, and Bac-GFP-PolΔ64, Bac-GFP-PolΔ110, and Bac-GFP-PolΔ186 showed 10-fold, 89-fold, and 891-fold reductions in infectious viral yield compared to that of the wild-type repair virus, respectively. Production of occlusion bodies was compromised for all truncation mutants. Further bioinformatic analysis showed that the first 64 amino acids (aa) at the extreme N terminus contains a conserved α(-helix)-β(-sheet)-β-β secondary-structure region, and further downstream sequence from aa 67 to 186 is comprised of four conserved sequence motifs. Multiple alanine point substitutions in the α-β-β-β structure region or the four sequence motifs in the N terminus impaired viral DNA replication and resulted in reduction of virus yield and occlusion body production. Together, our results suggested that the secondary structure and four conserved motifs within the N terminus of AcMNPV DNApol are important for viral DNA synthesis, infectious virus yield, and production of occlusion bodies. IMPORTANCE DNA polymerase (DNApol) is highly conserved in all baculoviruses and is required for viral DNA replication. The N terminus is one of the highly conserved regions of baculovirus DNApols. Our results showed that the N terminus of baculovirus DNA polymerase plays an important role in efficient viral DNA synthesis and infectious virus yield and production of occlusion bodies. We identified five features, including a highly conserved secondary structure and four conserved amino acid motifs, in the AcMNPV DNApol N terminus, all of which are important for efficient viral DNA synthesis, infectious virus yield, and production of occlusion bodies.
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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 | 0.001 |
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".