Effectiveness of specific RNA-mediated interference through ingested double-stranded RNA in Caenorhabditis elegans

Area of Science:

• Genetics
• Molecular Biology
• Developmental Biology

Background:

• RNA-mediated interference (RNAi) is a technique for gene silencing in C. elegans using double-stranded RNA (dsRNA).
• Gene silencing via feeding dsRNA-expressing bacteria is less labor-intensive but traditionally less efficient than direct dsRNA injection.
• Limited use of feeding RNAi has restricted its application despite its potential advantages.

Purpose of the Study:

• To optimize the feeding method for RNA-mediated interference (RNAi) in C. elegans.
• To demonstrate that optimized feeding RNAi can achieve gene silencing efficacy comparable to or exceeding direct injection.
• To explore the utility of feeding RNAi for gene function discovery and large-scale screening.

Main Methods:

• Development and optimization of a bacterial feeding protocol for dsRNA delivery in C. elegans.
• Systematic screening of random genes using the optimized feeding RNAi method.
• Titration of dsRNA feeding levels to uncover hypomorphic phenotypes.

Main Results:

• Optimized feeding RNAi produced phenotypes as strong as or stronger than direct dsRNA injection.
• The feeding RNAi method allowed for titration, revealing informative hypomorphic phenotypes.
• Screening identified functions for 13 previously uncharacterized genes, including genes affecting motility (ceh-6, MADS-box) and male incidence.

Conclusions:

• RNAi by feeding is a powerful tool for gene function discovery, offering advantages over injection.
• This method is suitable for specialized applications like titration, biochemistry, and large-scale genomic screens.
• Optimized feeding RNAi facilitates novel experimental approaches for utilizing genomic sequence data.