Intracellular expression of a fluorogenic DNA aptamer using retron Eco2.

Area of Science:

• Molecular Biology
• Biotechnology
• Synthetic Biology

Background:

• DNA aptamers are versatile molecules for therapeutics and diagnostics.
• Intracellular applications of aptamers are limited by challenges in in vivo expression.
• Bacterial retron systems offer potential for in vivo DNA synthesis.

Purpose of the Study:

• To investigate the feasibility of using the bacterial retron system for intracellular DNA aptamer expression.
• To demonstrate the biosynthesis of functional DNA aptamers within *Escherichia coli*.

Main Methods:

• Employed the Eco2 retron system in *Escherichia coli*.
• Engineered structure-guided insertion of a DNA light-up aptamer into the retron's non-coding region.
• Analyzed aptamer activity after intracellular synthesis and purification.

Main Results:

• Confirmed successful reverse transcription and biosynthesis of functional aptamer constructs via the retron system.
• Intracellularly synthesized DNA aptamers exhibited comparable activity to chemically synthesized controls.
• Demonstrated the potential for aptamer expression within living bacterial cells.

Conclusions:

• Retrons can be effectively utilized for expressing short DNA aptamers in living cells.
• This approach broadens the potential applications of aptamers in intracellular settings.
• Optimized intracellular aptamer expression may enhance therapeutic and diagnostic strategies.