The methyltransferase domain of the Sudan ebolavirus L protein specifically targets internal adenosines of RNA substrates, in addition to the cap structure
Bibliographic record
Abstract
Mononegaviruses, such as Ebola virus, encode an L (large) protein that bears all the catalytic activities for replication/transcription and RNA capping. The C-terminal conserved region VI (CRVI) of L protein contains a K-D-K-E catalytic tetrad typical for 2'O methyltransferases (MTase). In mononegaviruses, cap-MTase activities have been involved in the 2'O methylation and N7 methylation of the RNA cap structure. These activities play a critical role in the viral life cycle as N7 methylation ensures efficient viral mRNA translation and 2'O methylation hampers the detection of viral RNA by the host innate immunity. The functional characterization of the MTase+CTD domain of Sudan ebolavirus (SUDV) revealed cap-independent methyltransferase activities targeting internal adenosine residues. Besides this, the MTase+CTD also methylates, the N7 position of the cap guanosine and the 2'O position of the n1 guanosine provided that the RNA is sufficiently long. Altogether, these results suggest that the filovirus MTases evolved towards a dual activity with distinct substrate specificities. Whereas it has been well established that cap-dependent methylations promote protein translation and help to mimic host RNA, the characterization of an original cap-independent methylation opens new research opportunities to elucidate the role of RNA internal methylations in the viral replication.
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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".