Reconstitution of an Ultradian Oscillator in Mammalian Cells by a Synthetic Biology Approach

ACS Synth Biol. 2018 May 18;7(5):1447-1455. doi: 10.1021/acssynbio.8b00083. Epub 2018 May 10.


The Notch effector gene Hes1 is an ultradian clock exhibiting cyclic gene expression in several progenitor cells, with a period of a few hours. Because of the complexity of studying Hes1 in the endogenous setting, and the difficulty of imaging these fast oscillations in vivo, the mechanism driving oscillations has never been proven. Here, we applied a "build it to understand it" synthetic biology approach to construct simplified "hybrid" versions of the Hes1 ultradian oscillator combining synthetic and natural parts. We successfully constructed a simplified synthetic version of the Hes1 promoter matching the endogenous regulation logic. By mathematical modeling and single-cell real-time imaging, we were able to demonstrate that Hes1 is indeed able to generate stable oscillations by a delayed negative feedback loop. Moreover, we proved that introns in Hes1 contribute to the transcriptional delay but may not be strictly necessary for oscillations to occur. We also developed a novel reporter of endogenous Hes1 oscillations able to amplify the bioluminescence signal 5-fold. Our results have implications also for other ultradian oscillators.

Keywords: Hes1; delayed negative feedback; oscillations; single cell; synthetic promoter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Binding Sites
  • Biological Clocks / genetics*
  • CHO Cells
  • Carrier Proteins / genetics
  • Cricetulus
  • Doxycycline / pharmacology
  • Feedback, Physiological
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Introns
  • Mice
  • Models, Theoretical
  • Promoter Regions, Genetic
  • Protein Engineering / methods*
  • Single-Cell Analysis / methods
  • Sp3 Transcription Factor / genetics
  • Synthetic Biology / methods*
  • Transcription Factor HES-1 / genetics*
  • Transcription Factor HES-1 / metabolism*


  • Bacterial Proteins
  • Carrier Proteins
  • Hes1 protein, mouse
  • Tet O resistance protein, Bacteria
  • Transcription Factor HES-1
  • Green Fluorescent Proteins
  • Sp3 Transcription Factor
  • Doxycycline