Details

Autor(en) / Beteiligte

• de las Heras, Aitor
• Martínez-García, Esteban
• Domingo-Sananes, Maria Rosa
• Fraile, Sofia
• de Lorenzo, Víctor

Titel

Rationally rewiring the connectivity of the XylR/Pu regulatory node of the m-xylene degradation pathway in Pseudomonas putidaElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ib00310e

Erscheinungsjahr

2016-04

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The XylR/ Pu regulatory node of the m -xylene biodegradation pathway of Pseudomonas putida mt-2 is one of the most intricate cases of processing internal and external cues into a single controlling element. Despite this complexity, the performance of the regulatory system is determined in vivo only by the occupation of Pu by m -xylene-activated XylR and σ 54 -RNAP. The stoichiometry between these three elements defines natural system boundaries that outline a specific functional space. This space can be expanded artificially following different strategies that involve either the increase of XylR or σ 54 or both elements at the same time (each using a different inducer). In this work we have designed a new regulatory architecture that drives the system to reach a maximum performance in response to one single input. To this end, we first explored using a simple mathematical model whether the output of the XylR/ Pu node could be amended by simultaneously increasing σ 54 and XylR in response to only natural inducers. The exacerbation of Pu activity in vivo was tested in strains bearing synthetic transposons encoding xylR and rpoN (the σ 54 coding gene) controlled also by Pu , thereby generating a P. putida strain with the XylR/ Pu output controlled by two intertwined feed forward loops (FFLs). The lack of a negative feedback loop in the expression node enables Pu activity to reach its physiological maximum in response to a single input. Only competition for cell resources might ultimately check the upper activity limit of such a rewired m -xylene sensing device. Rational rewiring of the components of the sigma-54 dependent promoter Pu enables transcriptional output to reach its physiological limit.