A New Transgenic Tool to Study the Ret Signaling Pathway in the Enteric Nervous System.

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• The Ret receptor tyrosine kinase is vital for enteric nervous system (ENS) development, influencing progenitor cell proliferation, migration, and survival.
• While Ret's role in early ENS development is known, its function in neuronal differentiation and the adult ENS requires further investigation.
• Mutations in RET cause ENS disorders like Hirschsprung Disease, highlighting the need for better research tools.

Purpose of the Study:

• To develop a novel tool for visualizing Ret expression in live zebrafish during ENS development and in adulthood.
• To characterize the expression pattern of Ret in enteric progenitor cells and neurons throughout development.
• To assess the utility of the new tool in studying ENS development and disease models.

Main Methods:

• Generation of a BAC transgenic zebrafish line expressing Green Fluorescent Protein (GFP) under the control of the ret promoter (ret:GFP).
• Observation of GFP expression patterns in live zebrafish embryos and adults to monitor Ret activity.
• Analysis of ret:GFP expression in homozygous mutants for ret and sox10 genes.

Main Results:

• The ret:GFP line successfully visualizes Ret expression in enteric progenitor cells and most ENS neurons during development.
• GFP expression is observed in adult ENS neurons in both male and female zebrafish.
• Homozygous mutants for ret and sox10 exhibit a complete absence of GFP+ ENS cells, confirming the tool's specificity.

Conclusions:

• The developed ret:GFP zebrafish line is a valuable new tool for studying the Ret signaling pathway in the ENS from development to adulthood.
• This tool facilitates live imaging of Ret activity, aiding research into ENS development and diseases.
• The findings provide insights into the dynamic expression of Ret during neural development and its critical role in maintaining the adult ENS.