1 research outputs found
Reconstitution of an Ultradian Oscillator in Mammalian Cells by a Synthetic Biology Approach
The Notch effector
gene <i>Hes1</i> 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 <i>in vivo</i>, 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 <i>Hes1</i> 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 <i>Hes1</i> 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