Identification, molecular structure and expression of two cloned serotonin receptors from the pond snail, <i>Helisoma trivolvis</i>
Bibliographic record
Abstract
Helisoma trivolvis has served as a model system to study the functions of serotonin (5-HT) from cellular, developmental, physiological and behavioural perspectives. To further explore the serotonin system at the molecular level, and to provide experimental knockout tools for future studies, in this study we identified serotonin receptor genes from the H. trivolvis genome, and characterized the molecular structure and expression profile of the serotonin receptor gene products. Degenerate oligonucleotide primers, based on conserved regions of the Lymnaea stagnalis 5-HT(1Lym) receptor, were used to amplify G protein-coupled biogenic amine receptor sequences from H. trivolvis genomic cDNA, resulting in the cloning of two putative serotonin receptors. The deduced gene products both appear to be G protein-coupled serotonin receptors, with well-conserved structure in the functional domains and high variability in the vestibule entrance of the receptor protein. Phylogenetic analysis placed these receptors in the 5-HT(1) and 5-HT(7) families of serotonin receptors. They are thus named the 5-HT(1Hel) and 5-HT(7Hel) receptors, respectively. In situ hybridization and immunofluorescence studies revealed that these genes and gene products are expressed most heavily in the ciliated pedal and mantle epithelia of H. trivolvis embryos. In adults, widespread expression occurred in all ganglia and connectives of the central nervous system. Expression of both receptor proteins was localized exclusively to neurites when examined in situ. In contrast, when isolated neurons were grown in culture, 5-HT(1Hel) and 5-HT(7Hel) immunoreactivity were located primarily in the cell body. This is the first study to reveal a 5-HT(7) receptor in a molluscan species.
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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".