Transgenerational Sterility of a Transgenic C. elegans : A Cautionary Tale

Area of Science:

• Genetics and Molecular Biology
• Developmental Biology
• Biochemistry

Background:

• CRISPR-mediated integration of large fluorescent protein tags is often inefficient.
• Split fluorescent protein systems, like split-GFP and split-Scarlet, offer an alternative for fluorescent tagging in C. elegans.
• The glh-1 promoter drives germline gene expression, and T2A-mediated ribosomal skipping facilitates fusion protein production.

Purpose of the Study:

• To evaluate the long-term efficacy and potential side effects of using the glh-1::T2A::wrmScarlet(1-10) transgene in C. elegans.
• To investigate the impact of continuous culturing at elevated temperatures on the fertility of worms carrying this specific germline expression construct.

Main Methods:

• Generation and culturing of C. elegans strains carrying the glh-1::T2A::wrmScarlet(1-10) transgene.
• Monitoring brood size and fertility across generations under standard and elevated temperature conditions (25.5 °C).

Main Results:

• While initial observations suggested wild-type brood sizes at different temperatures, continuous culturing at 25.5 °C resulted in sterility in at least one tested line.
• This indicates a potential temperature-sensitive defect associated with the glh-1 driver and/or the T2A::wrmScarlet fusion protein.

Conclusions:

• The glh-1 driver and T2A::mScarlet fusions may not be suitable for long-term germline expression studies in C. elegans, especially at temperatures around 25.5 °C.
• Researchers should exercise caution when using this specific genetic construct, as it can lead to unexpected sterility.
• Further investigation is warranted to understand the molecular basis of this temperature-induced sterility.