Using transcription-based detectors to emulate the behavior of sequential probability ratio-based concentration...

Area of Science:

• Biophysics
• Systems Biology
• Biochemistry

Background:

• The sequential probability ratio test (SPRT) offers optimal decision speed for given error rates.
• Cells require accurate and rapid decision-making, suggesting SPRT's relevance for cellular processes.
• Implementing SPRT in cells typically requires biochemical circuits to compute log-likelihood ratios.

Purpose of the Study:

• To propose a transcription-based method that emulates SPRT's hit rate without direct log-likelihood ratio computation.
• To investigate the use of a promoter with multiple binding sites for detecting transcription factor concentration.
• To analyze the speed-accuracy tradeoff in cellular decision-making using a novel biological detector.

Main Methods:

• Developing a transcription-based detector utilizing a promoter with multiple binding sites.
• Modeling the binding and unbinding rates of a transcription factor to the promoter.
• Analyzing the probability of mRNA production exceeding a threshold to approximate SPRT's hit rate.

Main Results:

• Demonstrated that transcription factor binding/unbinding rates can be tuned to match SPRT hit rates.
• Showed that the transcription-based detector achieves a positive detection time less than or equal to SPRT.
• Confirmed that this approach emulates SPRT behavior without explicit log-likelihood ratio calculation.

Conclusions:

• A transcription-based detector can effectively emulate the SPRT's hit rate for cellular decision-making.
• This biological system offers a viable alternative to biochemical computation of log-likelihood ratios for SPRT.
• The developed method provides a potentially faster and accurate mechanism for cellular signal detection.