Conditional gene expression by controlling translation with tetracycline-binding aptamers.

Area of Science:

• Molecular Biology
• Synthetic Biology
• Biotechnology

Background:

• Conditional gene expression is crucial for research and biotechnology.
• Existing systems often rely on complex protein-based interactions or toxic inducers.
• RNA-based regulatory systems offer alternative control mechanisms.

Purpose of the Study:

• To develop a novel, tetracycline-inducible gene expression system in Saccharomyces cerevisiae.
• To utilize direct RNA-metabolite interactions for genetic control.
• To characterize the impact of aptamer insertion and stability on gene expression.

Main Methods:

• Insertion of tetracycline (tc) binding aptamers into the 5'-untranslated region (5'-UTR) of a GFP-encoding mRNA in yeast.
• Quantification of Green Fluorescent Protein (GFP) expression levels.
• Systematic modification of aptamer sequences and thermodynamic stability.
• Analysis of nucleotide positions influencing regulatory properties.

Main Results:

• Aptamer insertion generally reduced GFP expression.
• Specific aptamers demonstrated a tunable, up to 6-fold decrease in fluorescence upon tetracycline addition.
• Optimal regulation was achieved with aptamers positioned near the start codon.
• Aptamer thermodynamic stability directly correlated with regulatory efficiency and basal expression levels.
• Specific nucleotide mutations were identified that modulated either regulation or basal expression.

Conclusions:

• A facile and effective conditional gene expression system based on RNA-aptamer-tetracycline interaction was developed in yeast.
• The system offers precise control using a non-toxic, cell-permeable small molecule.
• This RNA-based system provides a valuable alternative for genetic manipulation in Saccharomyces cerevisiae and potentially other organisms.