A conditional knockout toolkit for Caenorhabditis elegans based on the Cre/loxP recombination.

Area of Science:

• Genetics
• Molecular Biology
• Developmental Biology

Background:

• Conditional knockout (cKO) is crucial for studying gene function in specific tissues and times.
• Caenorhabditis elegans (C. elegans) research has relied on mosaic analysis, rescue experiments, and RNA interference (RNAi) for spatial- and temporal-specific gene function studies.
• A stable and systematic cKO system is needed for C. elegans.

Purpose of the Study:

• To develop and validate a systematic and stable Cre/loxP-based conditional knockout (cKO) system in Caenorhabditis elegans (C. elegans).
• To enable precise spatial and temporal control over gene inactivation in C. elegans.
• To provide a versatile tool for functional genomics in C. elegans.

Main Methods:

• Generated Cre recombinase expression vectors driven by tissue-specific or heat-shock promoters.
• Validated Cre-mediated recombination using fluorescence protein systems.
• Established multi-copy Cre transgenic strains.
• Generated sid-1 deletion mutants with floxed sid-1 single-copy integration (SCI) using UV/TMP methods.
• Performed cKO in the hypodermis by crossing rescued sid-1 mutants with Pdpy-7::Cre strain.

Main Results:

• Demonstrated successful Cre-dependent loxP excision via fluorescence protein assays.
• Established a collection of Cre transgenic strains.
• Successfully generated conditional knockout of sid-1 in the hypodermis.
• sid-1 cKO animals exhibited resistance to bli-3 RNAi (hypodermal phenotype) and sensitivity to unc-22 RNAi (body wall muscle phenotype).

Conclusions:

• The developed Cre/loxP system provides a systematic approach for conditional knockout (cKO) in C. elegans.
• This system combines transgenic Cre collections, deletion mutants, and UV/TMP SCI methods for efficient gene function analysis.
• The established system facilitates precise spatiotemporal gene function studies in C. elegans.