Drosophila SPARC collagen IV chaperone-like activity essential for development is unique to the fat body
Bibliographic record
Abstract
fat body-derived SPARC acts as a chaperone for collagen IV (Col(IV)), enabling their diffusion and incorporation into distal tissue basement membranes (BMs). Disruption of SPARC or Col(IV) production by the fat body is lethal, despite expression by other tissues such as imaginal discs. Wing disc-derived SPARC does not associate with Col(IV) in BMs and is not essential for survival. We show that differential association of fat body- and wing disc-derived SPARC with Col(IV) is not due to differences in SPARC glycosylation nor to the absence of SPARC and Col(IV) co-expression. Further, we demonstrate that SPARC domain II/III produced by the fat body is sufficient for Col(IV) diffusion to both proximal and distal BMs, and rescues lethality associated with loss of SPARC. However, SPARC domain II/III does not diffuse beyond the hemolymph. Thus, the essential Col(IV) chaperone-like activity specific to fat body-derived SPARC is not required beyond the hemolymph.
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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".