Ventral neural patterning in the absence of a Shh activity gradient from the floorplate
Bibliographic record
Abstract
Background: Vertebrate spinal cord development requires Sonic Hedgehog (Shh) signaling from the floorplate and notochord, where it is thought to act in concentration dependent manner to pattern distinct cell identities along the ventral‐to‐dorsal axis. While in vitro experiments demonstrate naïve neural tissues are sensitive to small changes in Shh levels, genetic studies illustrate that some degree of ventral patterning can occur despite significant perturbations in Shh signaling. Consequently, the mechanistic relationship between Shh morphogen levels and acquisition of distinct cell identities remains unclear. Results: We addressed this using Hedgehog acetyltransferase ( Hhat Creface ) and Wiggable mouse mutants. Hhat encodes a palmitoylase required for the secretion of Hedgehog proteins and formation of the Shh gradient. In its absence, the spinal cord develops without floorplate cells and V3 interneurons. Wiggable is an allele of the Shh receptor Patched1 (Ptch1 Wig ) that is unable to inhibit Shh signal transduction, resulting in expanded ventral progenitor domains. Surprisingly, Hhat Creface/Creface ; Ptch1 Wig/Wig double mutants displayed fully restored ventral patterning despite an absence of Shh secretion from the floorplate. Conclusions: The full range of neuronal progenitor types can be generated in the absence of a Shh gradient provided pathway repression is dampened, illustrating the complexity of morphogen dynamics in vertebrate patterning. Developmental Dynamics 247:170–184, 2018 . © 2017 Wiley Periodicals, Inc.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".