Sulfatase modifying factors control the timing of zebrafish convergence and extension morphogenesis
Bibliographic record
Abstract
ABSTRACT To shape the emerging body plan, morphogenetic cell movements must be coordinated not only in space, but also in time. Convergence and Extension (C&E) movements that elongate the anteroposterior axis initiate with precise timing during vertebrate gastrulation, but the mechanisms controlling their onset remain unknown. We examined this question using zebrafish embryonic explants that faithfully recapitulate C&E cell movements and their precise timing in culture, in isolation from other gastrulation movements. We determined that new transcription is required at gastrulation onset for C&E in explants and identified sulfatase modifying factor 2 ( sumf2 ) as a candidate ‘trigger’ gene expressed at this time. sumf2 and its paralog sumf1 encode negative and positive regulators, respectively, of all sulfatase enzymes, which remove sulfate groups from their substrates, altering their biological activity. In zebrafish embryos and explants, sumf1 and sumf2 expression levels invert at gastrulation onset, predicting a reduction in sulfatase activity and consequent increase of substrate sulfation. We found that overexpressing sumf1 and sumf2 causes delayed or precocious C&E onset, respectively, whereas loss of sumf1 and sumf2 function shifts C&E timing in the opposite direction. We further identified Sulf1, an extracellular sulfatase that modifies heparan sulfate proteoglycans (HSPGs), as the key effector by which sumf1 and sumf2 control C&E timing. Accordingly, reduced or increased levels of sulfated heparan sulfate similarly shift C&E onset and suppress sumf1 and sumf2 mutant phenotypes. Together, our work supports a model in which sumf2 expression at zebrafish gastrulation onset reduces sulfatase activity, rewriting HSPG sulfation patterns to promote and/or permit C&E morphogenesis.
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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".