scholarly journals Winner-takes-all resource competition redirects cascading cell fate transitions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rong Zhang ◽  
Hanah Goetz ◽  
Juan Melendez-Alvarez ◽  
Jiao Li ◽  
Tian Ding ◽  
...  

AbstractFailure of modularity remains a significant challenge for assembling synthetic gene circuits with tested modules as they often do not function as expected. Competition over shared limited gene expression resources is a crucial underlying reason. It was reported that resource competition makes two seemingly separate genes connect in a graded linear manner. Here we unveil nonlinear resource competition within synthetic gene circuits. We first build a synthetic cascading bistable switches (Syn-CBS) circuit in a single strain with two coupled self-activation modules to achieve two successive cell fate transitions. Interestingly, we find that the in vivo transition path was redirected as the activation of one switch always prevails against the other, contrary to the theoretically expected coactivation. This qualitatively different type of resource competition between the two modules follows a ‘winner-takes-all’ rule, where the winner is determined by the relative connection strength between the modules. To decouple the resource competition, we construct a two-strain circuit, which achieves successive activation and stable coactivation of the two switches. These results illustrate that a highly nonlinear hidden interaction between the circuit modules due to resource competition may cause counterintuitive consequences on circuit functions, which can be controlled with a division of labor strategy.

Author(s):  
Rong Zhang ◽  
Hanah Goetz ◽  
Juan Melendez-Alvarez ◽  
Jiao Li ◽  
Tian Ding ◽  
...  

AbstractFailure of modularity remains a significant challenge for synthetic gene circuits assembled with tested modules as they often do not function as expected. Competition over shared limited gene expression resources is a crucial underlying reason. Here, we first built a synthetic cascading bistable switches (Syn-CBS) circuit in a single strain with two coupled self-activation modules to achieve two successive cell fate transitions. Interestingly, we found that the in vivo transition path was redirected as the activation of one switch always prevailed against the other instead of the theoretically expected coactivation. This qualitatively different type of resource competition between the two modules follows a ‘winner-takes-all’ rule, where the winner is determined by the relative connection strength between the modules. To decouple the resource competition, we constructed a two-strain circuit, which achieved successive activation and stable coactivation of the two switches. We unveiled a nonlinear resource competition within synthetic gene circuits and provided a division of labor strategy to minimize unfavorable effects.


2021 ◽  
pp. 1-18
Author(s):  
Andrew Lezia ◽  
Arianna Miano ◽  
Jeff Hasty

Author(s):  
Barbara Jusiak ◽  
Ramiz Daniel ◽  
Fahim Farzadfard ◽  
Lior Nissim ◽  
Oliver Purcell ◽  
...  

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia Calero ◽  
Daniel C. Volke ◽  
Phillip T. Lowe ◽  
Charlotte H. Gotfredsen ◽  
David O’Hagan ◽  
...  

Abstract Fluorine is a key element in the synthesis of molecules broadly used in medicine, agriculture and materials. Addition of fluorine to organic structures represents a unique strategy for tuning molecular properties, yet this atom is rarely found in Nature and approaches to integrate fluorometabolites into the biochemistry of living cells are scarce. In this work, synthetic gene circuits for organofluorine biosynthesis are implemented in the platform bacterium Pseudomonas putida. By harnessing fluoride-responsive riboswitches and the orthogonal T7 RNA polymerase, biochemical reactions needed for in vivo biofluorination are wired to the presence of fluoride (i.e. circumventing the need of feeding expensive additives). Biosynthesis of fluoronucleotides and fluorosugars in engineered P. putida is demonstrated with mineral fluoride both as only fluorine source (i.e. substrate of the pathway) and as inducer of the synthetic circuit. This approach expands the chemical landscape of cell factories by providing alternative biosynthetic strategies towards fluorinated building-blocks.


2017 ◽  
Vol 1 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Huijuan Wang ◽  
Maurice H.T. Ling ◽  
Tze Kwang Chua ◽  
Chueh Loo Poh

2019 ◽  
Author(s):  
Javier Santos-Moreno ◽  
Eve Tasiudi ◽  
Joerg Stelling ◽  
Yolanda Schaerli

AbstractGene expression control based on CRISPRi (clustered regularly interspaced short palindromic repeats interference) has emerged as a powerful tool for creating synthetic gene circuits, both in prokaryotes and in eukaryotes; yet, its lack of cooperativity has been pointed out as a potential obstacle for dynamic or multistable circuit construction. Here we use CRISPRi to build prominent synthetic gene circuits in Escherichia coli. We report the first-ever CRISPRi oscillator (“CRISPRlator”), bistable network (toggle switch) and stripe pattern-forming incoherent feed-forward loop (IFFL). Our circuit designs, conceived to feature high predictability and orthogonality, as well as low metabolic burden and context-dependency, allowed us to achieve robust circuit behaviors. Mathematical modeling suggests that unspecific binding in CRISPRi is essential to establish multistability. Our work demonstrates the wide applicability of CRISPRi in synthetic circuits and paves the way for future efforts towards engineering more complex synthetic networks, boosted by the advantages of CRISPR technology.


Sign in / Sign up

Export Citation Format

Share Document