Architecture-dependent noise discriminates functionally analogous differentiation circuits.
Gene regulatory circuits with different architectures (patterns of regulatory interactions) can generate similar dynamics. This raises the question of why a particular circuit architecture is selected to implement a given cellular process. To investigate this problem, we compared the Bacillus subtilis circuit that regulates differentiation into the competence state to an engineered circuit with an alternative architecture (SynEx) in silico and in vivo. Time-lapse microscopy measurements showed that SynEx cells generated competence dynamics similar to native cells and reconstituted the physiology of differentiation. However, architectural differences between the circuits altered the dynamic distribution of stochastic fluctuations (noise) during circuit operation. This distinction in noise causes functional differences between the circuits by selectively controlling the timing of competence episodes and response of the system to various DNA concentrations. These results reveal a tradeoff between temporal precision and physiological response range that is controlled by distinct noise characteristics of alternative circuit architectures.
Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
Tolga
T
Cağatay
Marc
M
Turcotte
Michael B
MB
Elowitz
Jordi
J
Garcia-Ojalvo
Gürol M
GM
Süel
D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D004247:DNA / Q000378:metabolism; D005246:Feedback; D015964:Gene Expression Regulation, Bacterial; D053263:Gene Regulatory Networks; D008954:Models, Biological; D014169:Transformation, Bacterial
D004247:DNA