RNAi pathways contribute to developmental history-dependent phenotypic plasticity in C. elegans

Area of Science:

• Developmental Biology
• Epigenetics
• RNA Biology

Background:

• Early environmental exposures can alter adult characteristics through poorly understood mechanisms.
• Adult Caenorhabditis elegans exposed to a stress-induced dauer stage show altered gene expression, chromatin states, and life history traits compared to controls.
• These molecular differences suggest distinct developmental trajectories influenced by early life experiences.

Purpose of the Study:

• To investigate the mechanisms underlying developmental history-dependent phenotypes in C. elegans.
• To profile small RNAs in post-dauer and control adult C. elegans to identify regulatory pathways.
• To understand the role of RNA interference (RNAi) in mediating epigenetic reprogramming due to early life stress.

Main Methods:

• Deep sequencing of small RNAs from post-dauer and control adult C. elegans.
• Quantification of endogenous small interfering RNA (endo-siRNA) levels.
• Analysis of gene expression and chromatin states.
• Mutational analysis of specific endo-siRNA pathways.

Main Results:

• A subset of genes was identified as targets of developmental history-dependent reprogramming via RNAi-mediated mechanisms.
• Mutations in endo-siRNA pathways disrupted expected gene expression and chromatin changes in post-dauer animals, affecting their increased brood size.
• Dauer larvae exhibit unique chromatin states and endo-siRNA distribution, potentially serving as a template for adult epigenetic profiles.

Conclusions:

• Endogenous small interfering RNA (endo-siRNA) pathways play a role in early experience-dependent phenotypic plasticity.
• Developmental history can program adult physiology and behavior through epigenetic mechanisms involving small RNAs.
• The dauer larval stage and its associated molecular remodeling are critical for establishing long-term adult phenotypes.