Abstract 531: Mutagenic Gene Trapping to Study Novel Genes in Zebrafish Cardiovascular Development
Bibliographic record
Abstract
The zebrafish has emerged as an excellent model for cardiovascular research thanks to its ex-utero and rapid embryonic development, its embryonic transparent nature, and its capacity to survive in the absence of a functional cardiovascular system during the first week of development, which enables functional characterization of mutations that would otherwise induce lethality in traditional murine models. The aim of this project is to identify and characterize novel genes involved in zebrafish cardiovascular development using mutagenic gene trapping, a technique that generates random insertional mutations across the genome. We use the well-defined RP2 gene-breaking transposon system, which not only mutates, but also fluorescently tags the trapped gene product(s) (Clark, Nat Methods, 2011). RP2 also introduces loxP sites into the mutant locus, which can be used for Cre-mediated phenotype rescue by microinjection of Cre recombinase, or by crossing to tissue-specific Cre lines. From over 3000 RP2-injected embryos, 141 fish showed germline transmission. Among them, 51 expressed strong fluorescence in different tissues, including the heart, vessels, notochord, central nervous system (CNS), and eyes. Three cardiovascular lines were selected for phenotypic characterization and functional studies. RP2#C2 strain expressed fluorescence in the heart valves, CNS, eyes and pectoral fin buds. Inverse PCR in RP2#C2 demonstrated a trapped gene at meis4.1a, which encodes a homeobox transcription factor that has not been previously studied in zebrafish. RP2#121 strain expressed strong fluorescence in cardiac and skeletal muscles. RP2#91 strain showed expression in the vasculature and demonstrated a trapped gene at pdgfra. Homozygous RP2#91 mutants showed severe defects in the heart, blood flow, and other body parts including the head and musculature. We are currently creating a panel of tissue-specific Cre lines targeting tissues such as cardiomyocytes, endothelial cells and smooth muscle cells for spatiotemporal rescuing of the mutant phenotype. The generated zebrafish protein-trap lines are invaluable tools to annotate gene function, dissect the molecular mechanisms of cardiovascular development, and potentially serve as disease models.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".