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Zebrafish stat3 is expressed in restricted tissues during embryogenesis and stat1 rescues cytokine signaling in a
A C Oates1, P Wollberg, S J Pratt
1Ludwig Institute for Cancer Research, Melbourne Tumour Biology Branch, Royal Melbourne Hospital, Victoria, Australia. aoates@molbio.princeton.edu
Abstract:
Transcription factors of the STAT family are required for cellular responses to multiple signaling molecules. After ligand binding-induced activation of cognate receptors, STAT proteins are phosphorylated, hetero- or homodimerize, and translocate to the nucleus. Subsequent STAT binding to specific DNA elements in the promoters of signal-responsive genes alters the transcriptional activity of these loci. STAT function has been implicated in the transduction of signals for growth, reproduction, viral defense, and immune regulation. We have isolated and characterized two STAT homologs from the zebrafish Danio rerio. The stat3 gene is expressed in a tissue-restricted manner during embryogenesis, and larval development with highest levels of transcript are detected in the anterior hypoblast, eyes, cranial sensory ganglia, gut, pharyngeal arches, cranial motor nuclei, and lateral line system. In contrast, the stat1 gene is not expressed during early development. The stat3 gene maps to a chromosomal position syntenic with the mouse and human STAT3 homologs, whereas the stat1 gene does not. Despite a higher rate of evolutionary change in stat1 relative to stat3, the stat1 protein rescues interferon-signaling functions in a STAT1-deficient human cell line, indicating that cytokine-signaling mechanisms are likely to be conserved between fish and tetrapods. Dev Dyn 1999;215:352-370.
Insights
Researchers identified two STAT (Signal Transducer and Activator of Transcription) gene homologs in zebrafish. Stat3 shows specific expression during development, while stat1 rescues human cell function, indicating conserved signaling pathways.
Area of Science:
- Molecular Biology
- Developmental Biology
- Genetics
Background:
- Signal transducer and activator of transcription (STAT) proteins mediate cellular responses to signaling molecules.
- STATs are crucial for growth, reproduction, viral defense, and immune regulation.
- Understanding STAT function in diverse organisms provides insights into conserved biological processes.
Purpose of the Study:
- To isolate and characterize two STAT homologs in zebrafish (Danio rerio).
- To investigate the expression patterns and chromosomal mapping of zebrafish stat genes.
- To assess the functional conservation of zebrafish STAT proteins.
Main Methods:
- Isolation and characterization of zebrafish STAT homologs.
- Analysis of gene expression patterns during zebrafish embryogenesis and larval development.
- Chromosomal mapping of zebrafish stat genes.
- Functional complementation assay using a STAT1-deficient human cell line.
Main Results:
- Two STAT homologs, stat3 and stat1, were identified in zebrafish.
- Zebrafish stat3 exhibits tissue-restricted expression during embryogenesis and larval development.
- Zebrafish stat1 does not show expression during early development but rescues interferon-signaling defects in a human cell line.
- Zebrafish stat3 maps to a syntenic position with human and mouse STAT3, while stat1 does not.
Conclusions:
- Zebrafish stat3 plays a role in embryonic and larval development.
- Despite evolutionary divergence, zebrafish stat1 retains functional conservation in interferon signaling.
- These findings suggest conserved cytokine-signaling mechanisms between fish and tetrapods.