Alternative Splicing of Xenopus α <sub>fast</sub> -Tropomyosin Pre-mRNA during Development: Identification of Determining Sequences
Bibliographic record
Abstract
The Xenopus alphafast-tropomyosin gene contains in its central part a set of mutually exclusive exons, designated 6A and 6B, which are incorporated into mRNA encoding, respectively, nonmuscle and muscle tropomyosins. In this study, we show that usage of both exons is strictly regulated during development, exon 6A being used in the oocyte and nonmuscle tissues of the embryo, while exon 6B is used in muscle tissues. An approach of transient embryo transgenesis was developed to study the mechanisms involved in the splice site choice during development. We demonstrate that a-tropomyosin minigenes driven by tissue-specific promoters that target gene expression in nonmuscle and muscle tissues recapitulate the splicing pattern of the endogenous gene. A mutational analysis showed that regulation occurred at both exons 6A and 6B in muscle and nonmuscle tissues. In this context, we have identified an element located in the intron downstream of 6A that participates in the recognition of the weak 5' splice site of exon 6A and the repression of exon 6B in nonmuscle cells.
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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".