A "FLP-Out" system for controlled gene expression in Caenorhabditis elegans

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Precise control over gene expression is crucial for understanding complex biological processes.
• Conditional gene expression systems allow for temporal and spatial regulation of gene activity.
• The FRT/FLP recombinase system offers a powerful tool for genetic manipulation in various organisms.

Purpose of the Study:

• To develop and validate a two-part conditional FLP-out system for FRT-flanked sequences in *Caenorhabditis elegans*.
• To assess the system's efficacy for cell lineage marking and gene activity control.
• To investigate the role of *hlh-12* in distal tip cell (DTC) migration using conditional expression.

Main Methods:

• Conditional FLP-out system utilizing FRT sites and FLP recombinase.
• Reporter gene assays to evaluate system efficacy.
• Construction and testing of a dominant-negative *hlh-12* allele.
• RNA interference (RNAi) for *hlh-12* gene knockdown.
• Heat-inducible FLP recombinase for temporal control.
• Distal tip cell (DTC) migration assays.
• Development of traditional and Gateway-compatible vectors.

Main Results:

• Demonstrated successful conditional FLP-out of FRT-flanked sequences in *C. elegans*.
• Validated the system's utility as a cell lineage marking tool.
• Showed that conditional expression of a dominant-negative *hlh-12* allele interferes with DTC migration.
• Confirmed that conditional *hlh-12* RNAi also induces DTC migration defects.
• Developed versatile vectors to facilitate the application of this technology.

Conclusions:

• The developed conditional FLP-out system provides robust spatial and temporal control over gene activity in *C. elegans*.
• This system is effective for cell lineage tracing and functional studies of gene requirements, such as *hlh-12* in DTC migration.
• The provided vector set simplifies the implementation of this technology for diverse research applications.