Left-right patterning in the C. elegans embryo: Unique mechanisms and common principles.

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Genetics

Background:

• Bilateral symmetry evolved ~600 million years ago, enabling efficient locomotion and cephalization.
• Chirality, or left-right asymmetry, enhances organismal function, seen in nervous system lateralization and organ asymmetry.
• Mechanisms maintaining left-right asymmetry during development are largely unknown in most bilaterians.

Purpose of the Study:

• To review mechanisms coupling early embryonic left-right (L-R) symmetry breaking to subsequent L-R patterning.
• To highlight insights from the roundworm Caenorhabditis elegans model system.
• To present evidence for conserved mechanisms in organismal L-R patterning.

Main Methods:

• Review of existing literature on L-R patterning in Caenorhabditis elegans.
• Discussion of a specific L-R patterning strategy involving spatial separation of midline and anteroposterior axes.
• Analysis of the roles of rotational cellular rearrangement and non-canonical Wnt signaling.

Main Results:

• A strategy for L-R patterning in early C. elegans embryos involves rotational cellular rearrangement and non-canonical Wnt signaling.
• This process spatially separates the midline and anteroposterior axes.
• Evidence suggests rotational rearrangements and non-canonical Wnt signaling are broadly relevant for L-R patterning.

Conclusions:

• Early embryonic symmetry breaking is coupled to L-R patterning through conserved mechanisms.
• Rotational cellular rearrangements and non-canonical Wnt signaling are key players in establishing and maintaining L-R asymmetry.
• Understanding these mechanisms in C. elegans provides general insights into developmental biology.