“Reverse torpedoes“ model for the termination and processing of U3 snoRNA
Bibliographic record
Abstract
While the termination of transcription and 3′ RNA processing of the eukaryotic mRNA has been linked to a polyadenylation signal and a transcript cleavage process, much less is known about the termination or processing of non polyadenylated pol II transcripts. An efficiently expressed plasmid‐based expression system was used to study the termination and processing of S. pombe U3 snoRNA transcripts in vivo . The termination assay was linked to cell transformation and restriction fragment length polymorphism was used to determine levels of plasmid‐derived U3 snoRNA. Mutation analyses in vivo indicate that the maturation of the 3′ end is not directly dependent on an external cis‐acting sequence or structure; rather, it is dependent on a transcript cleavage which can occur hundreds or even thousands of nucleotides downstream of the mature U3 snoRNA sequence. Similarly, termination is dependent on transcript cleavage which is localized in a hairpin structure that normally follows the 3′ end of the U3 snoRNA but, which also can be moved hundreds or thousands of nucleotides downstream. Both processes, however, can be induced simultaneously and equally efficiently with a single unrelated Pac 1 endonuclease‐labile structure. The results support a “reverse torpedoes” model in which a single cleavage allows exonuclease access to the transcript leading to transcription termination in one direction and RNA maturation in the other direction. Supported by the Natural Sciences and Engineering Research Council of Canada.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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".