A Robust Molecular Network Motif for Period-Doubling Devices

Area of Science:

• Synthetic Biology
• Systems Biology
• Biomolecular Engineering

Background:

• Biological systems rely on cyclic processes (e.g., cell division) driven by periodic signals.
• Coordinating biological processes operating at different timescales requires period modulation of master clocks.
• Designing biological frequency dividers analogous to electronic flip-flops remains a challenge.

Purpose of the Study:

• To propose and analyze biomolecular circuits capable of period-doubling (frequency division).
• To investigate different biomolecular realizations of a proposed network motif.
• To assess the robustness and feasibility of these circuits in biological systems.

Main Methods:

• Inspired by electronic flip-flop architecture, a network motif combining a bistable switch and negative feedback was designed.
• Three biomolecular realizations were proposed: two transcriptional gene networks and one nucleic acid strand displacement system.
• Mathematical tools from algebraic geometry and numerical sensitivity analysis were used to study circuit behavior and robustness.

Main Results:

• The proposed motif can be realized using various biomolecular components, maintaining bistability with input modulation.
• Transcriptional network realizations demonstrated correct period-doubling, even in stochastic conditions with the repressilator oscillator.
• Sensitivity analysis confirmed the motif's robustness across a range of parameters and different realizations.

Conclusions:

• The proposed biomolecular period-doubling network motif is a viable strategy for frequency division in synthetic biology.
• The motif's robustness suggests experimental feasibility using diverse components from synthetic biology libraries.
• This work provides a foundation for building complex biological circuits that coordinate processes across different timescales.