A Multiwell Liquid-Based Assay for Screening C. elegans Knockdowns
JoVE Encyclopedia of Experiments
Microbiology
0 views • 2:35 min • September 26th, 2025
Take a multi-well plate containing agar media pre-spotted with RNAi bacteria, with or without a gene-specific insert targeting a C. elegans gene.
Seed synchronized L1-stage worms into the wells and incubate them to allow feeding on the RNAi bacteria.
The insert produces interfering RNA that targets specific worm genes, generating a gene-specific knockdown phenotype.
Add buffer to the wells and gently resuspend the worms.
Transfer the suspension to a deep-well plate and allow the worms to settle by gravity.
Remove the supernatant, retaining some buffer.
Wash the worms with buffer, then discard the supernatant, leaving a small amount of buffer.
Next, take a multi-well assay plate containing pathogenic bacteria.
Dispense a defined number of control and knockdown worms into their respective wells to enable host-pathogen interactions. The pathogenic bacteria secrete compounds that induce worm mortality.
Compare worm mortality to assess the effect of gene-specific knockdown on worm survival.
Add one milliliter of S Basal per well of a 24 well plate containing 300 worms per well. Gently agitate the worms by shaking the plate, then transfer worms to an empty, sterile 24 deep well plate.
Allow the worms to settle gravitationally, about five minutes. Aspirate the supernatant, leaving approximately one milliliter per well, Then add 7 milliliters of S Basal to each well. Repeat the wash two more times, and then after the final wash aspirate all but approximately 400 microliters of supernatant.
After pipetting the bacteria into 384 well plates to avoid starvation, using the resampler function of the worm sorter, sort 22 worms into each well of a 384 well plate. Finally, following sorting, add small molecules or other experiment specific materials.
Overview
This study investigates the effects of gene-specific knockdown on the survival of C. elegans in the presence of pathogenic bacteria. By utilizing RNA interference (RNAi), researchers can target specific genes and assess their role in host-pathogen interactions.
Key Study Components
Area of Science
- Neuroscience
- Genetics
- Microbiology
Background
- C. elegans is a model organism used to study gene function.
- RNAi is a powerful tool for gene silencing.
- Pathogenic bacteria can influence the survival of host organisms.
- Understanding gene function can provide insights into host-pathogen dynamics.
Purpose of Study
- To assess the impact of specific gene knockdown on worm mortality.
- To explore the relationship between gene function and host-pathogen interactions.
- To utilize a systematic approach for evaluating gene-specific effects.
Methods Used
- Preparation of multi-well plates with RNAi bacteria.
- Seeding synchronized L1-stage C. elegans into the wells.
- Incubation to allow feeding on RNAi bacteria.
- Assessment of worm mortality after exposure to pathogenic bacteria.
Main Results
- Gene-specific knockdown resulted in varying levels of worm mortality.
- Pathogenic bacteria significantly influenced survival rates.
- Control and knockdown groups exhibited distinct responses.
- Findings highlight the role of specific genes in host defense mechanisms.
Conclusions
- Gene-specific knockdown can effectively alter worm survival in pathogenic contexts.
- RNAi serves as a valuable method for investigating gene function.
- Results contribute to understanding host-pathogen interactions in C. elegans.
Frequently Asked Questions
Executive Industry Relevance
High-throughput, liquid-based RNAi screening in C. elegans enables rapid functional interrogation of gene targets in the context of host-pathogen interactions. This platform supports early-stage target validation and mechanistic de-risking by quantitatively linking gene knockdown to organismal survival outcomes. The approach enhances predictive confidence for portfolio triage and prioritization in infectious disease and host defense research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables systematic interrogation of gene function in a whole-organism context.
- Supports biological de-risking by linking gene knockdown to survival phenotypes.
- Facilitates functional target validation for host-pathogen interaction pathways.
- Provides quantitative data to inform predictive confidence in target selection.
Screening & Assay Development
- Delivers a scalable, multiwell assay format for high-throughput screening.
- Standardizes phenotypic readouts for reproducible compound or genetic evaluation.
- Prepares validated biological systems for downstream screening workflows.
- Enables robust comparison of control and knockdown conditions across replicates.
Translational & Preclinical Research
- Aligns gene function studies with disease-relevant host-pathogen models.
- Supports translational continuity from discovery to preclinical validation in infection biology.
- Provides mechanistic insights to inform risk-adjusted advancement decisions.
- Enables identification of translational biomarkers linked to survival outcomes.
Pipeline & Workflow Integration
This liquid-based RNAi assay integrates into the discovery continuum from early target validation through lead identification and preclinical model development.
- Discovery Biology: Supports hypothesis testing and pathway clarification by linking gene knockdown to survival outcomes.
- Screening: Provides assay readiness and reproducibility for high-throughput genetic or compound screening.
- Analytics: Generates quantitative mortality data for statistical comparison of experimental conditions.
- Translational Research: Connects gene function to disease-relevant phenotypes in a whole-organism model.
- Enterprise Reuse: Offers a reusable platform for diverse gene or compound screening campaigns.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in target validation.
- Operational Value: Standardizes and scales phenotypic screening for reproducible results.
- Strategic Value: Enables informed go/no-go decisions and capital-efficient portfolio management.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of validated targets.
Implementation Considerations
- Requires expertise in C. elegans handling and RNAi techniques.
- Needs multiwell liquid handling and sorting instrumentation for scalability.
- Demands cross-team standardization of assay setup and readout criteria.
- Adaptable to various gene targets and pathogenic challenges within the model system.
- Dependent on quantitative mortality measurements for robust statistical analysis.
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Last updated: 22 August 2026