Initial characterization of Wnt-Tcf functions during Ciona heart development

Area of Science:

• Developmental biology
• Molecular signaling

Background:

• The cardiopharyngeal mesoderm forms cardiac and head muscles in vertebrates.
• Canonical Wnt signaling influences cardiomyocyte specification and muscle development.
• The role of Wnt signaling in ascidian cardiopharyngeal development is largely unknown.

Purpose of the Study:

• To investigate Wnt signaling's role in ascidian cardiopharyngeal development.
• To examine the impact of Wnt signaling and Tcf on heart versus pharyngeal muscle fate.
• To generate tools for studying Wnt signaling in Ciona.

Main Methods:

• Documented Wnt pathway component expression in Ciona.
• Generated tools for functional Wnt signaling analysis.
• Performed Tcf knock-down using CRISPR/Cas9.
• Conducted lineage-specific transcriptome profiling.

Main Results:

• Tcf showed no significant role in early cardiac versus pharyngeal muscle fate choice.
• Wnt gene expression patterns and Tcf knock-down indicated a later requirement for Wnt signaling.
• Wnt signaling is implicated in later heart morphogenesis and/or cardiomyocyte differentiation.

Conclusions:

• Wnt signaling is not essential for early muscle fate determination in Ciona cardiopharyngeal development.
• Wnt signaling plays a critical role in later stages of heart organogenesis and cardiomyocyte differentiation.
• This study provides valuable reagents and insights for future research on Wnt signaling in ascidian heart development.