Single-minded 2 is required for left-right asymmetric stomach morphogenesis

Area of Science:

• Developmental Biology
• Genetics
• Evolutionary Biology

Background:

• Left-right (LR) asymmetry is vital for organogenesis, with stomach curvature being an early indicator in the digestive tract.
• Understanding the molecular mechanisms of this asymmetry is key to comprehending normal development and related birth defects.

Purpose of the Study:

• To identify genes responsible for the leftward curvature of the developing stomach in frog embryos.
• To elucidate the role of asymmetric gene expression in establishing digestive tract laterality.

Main Methods:

• Transcriptome analysis comparing the left and right sides of developing frog stomachs.
• Functional studies to determine the role of identified asymmetric genes in driving stomach curvature.

Main Results:

• Single-minded 2 (sim2), a homolog of the Drosophila sim gene, was the only gene besides pitx2 consistently expressed asymmetrically during stomach curvature.
• sim2 acts downstream of LR patterning cues to regulate cellular behaviors in the left stomach epithelium, driving asymmetric curvature.

Conclusions:

• The study reveals convergent co-option of single-minded genes in the evolution of LR asymmetric morphogenesis across species.
• Findings suggest potential dose-dependent roles for laterality factors in non-laterality-related birth defects.