Dissection of zebrafish shha function using site-specific targeting with a Cre-dependent genetic switch

Area of Science:

• Developmental Biology
• Regenerative Medicine
• Genetics

Background:

• Zebrafish are crucial model organisms for studying development and regeneration.
• Existing genetic techniques for conditional gene analysis in zebrafish are limited, hindering research.
• A need exists for advanced genetic tools to precisely investigate gene function.

Purpose of the Study:

• To introduce Zwitch, a novel Cre-dependent invertible gene-trap cassette for zebrafish.
• To establish a method for creating conditional alleles through intronic insertions via homologous recombination.
• To demonstrate the application of Zwitch in studying gene function during development and regeneration.

Main Methods:

• Generation of the Zwitch cassette for Cre-dependent gene trapping.
• Creation of a conditional sonic hedgehog a (shha) allele using Zwitch.
• Utilizing a global Cre driver to assess shha function in homozygous mutants.
• Employing an epicardium-specific inducible Cre driver to analyze Shha's role in heart development.

Main Results:

• Zwitch enables conditional gene knockout in zebrafish via intronic insertions.
• Conditional shha mutants exhibited reduced shha expression and developmental defects when Cre was present.
• Epicardium-specific Shha is critical for myocardial proliferation in heart development and regeneration.
• Zebrafish homozygous shha mutants showed normal development without Cre expression.

Conclusions:

• Zwitch significantly enhances the capability for conditional gene analysis in zebrafish.
• The tool facilitates detailed investigation of gene function in organ development and regeneration.
• Zwitch holds potential for application in other model organisms for genetic research.