The Timing of Transcriptional Regulation in Synthetic Gene Circuits
Author
Cheng, Yu-Yu; Hirning, Andrew J.; Josić, Krešimir; Bennett, Matthew R.
Date
2017Abstract
Transcription factors and their target promoters are central to synthetic biology. By arranging these components into novel gene regulatory circuits, synthetic biologists have been able to create a wide variety of phenotypes, including bistable switches, oscillators, and logic gates. However, transcription factors (TFs) do not instantaneously regulate downstream targets. After the gene encoding a TF is turned on, the gene must first be transcribed, the transcripts must be translated, and sufficient TF must accumulate in order to bind operator sites of the target promoter. The time to complete this process, here called the “signaling time,” is a critical aspect in the design of dynamic regulatory networks, yet it remains poorly characterized. In this work, we measured the signaling time of two TFs in Escherichia coli commonly used in synthetic biology: the activator AraC and the repressor LacI. We found that signaling times can range from a few to tens of minutes, and are affected by the expression rate of the TF. Our single-cell data also show that the variability of the signaling time increases with its mean. To validate these signaling time measurements, we constructed a two-step genetic cascade, and showed that the signaling time of the full cascade can be predicted from those of its constituent steps. These results provide concrete estimates for the time scales of transcriptional regulation in living cells, which are important for understanding the dynamics of synthetic transcriptional gene circuits.
Citation
Published Version
Type
Journal article
Publisher
Citable link to this page
https://hdl.handle.net/1911/98814Rights
This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society.Metadata
Show full item recordCollections
- Bioengineering Publications [632]
- BioSciences Publications [365]
- Faculty Publications [4990]