Team:Peking S/project/wire

Chemical Wire Toolbox

Introduction|Harvesting ‘Chemical Wires’ From Nature|Synthesizing Quorum Sensing Inverters|Orthogonal Activating Matrix

Harvesting ‘Chemical Wires’ From Nature

Introduction

Multicellular strategy provides us a vista to construct a complex gene network. During gene network constructing, as genetic network scaling up, more cells are involved in compartmentalizing genetic network. Natural quorum sensing and small chemical molecule generator and receiver systems provide a potential platform for multicellular network construction. Unfortunately, naturally existing and well characterized cell-cell communication systems are far from sufficient. Thus， exploiting new systems is significantly important in multicellular network construction using synthetic microbial consortia.

In exploiting new systems many molecules could serve as candidates of synthetic consortia ‘chemical wire’, but not all of them perform well when applied to microbial chassis. One of the most significant problems is that they are difficult to be synthesized or perceived when chemical molecule generating or receiving mechanism is too complex to engineer. Besides, threshold, response time and coordination of receiver cell performance should also be considered in cell-cell communication system selection. Because only ‘chemical wire’ systems with low threshold, high response speed and coordination response deserve to be converted into signaling-system-compartment. According to the selection principles above， in our project two signal generators and receiver systems are selected. One employs autoinducer N-(3-hydroxy-7-cis-tetradecenoyl)-L-homoserine lactone (3OH-C14:1-HSL), as the signal molecule (Figure 1). The other system employs Salicylate (Figure 2).In order to confirm their usability in practical application, we designed experiments covering three aspects of the systems, namely dose response, time dependence and coordination.

Cin system

This system derives from Rhizobium leguminosarum which are Gram-negative soil bacteria living in symbiotic association with legumes by forming nodules. In this system, cinI, pcin, cinR are the core elements involved in cin system. CinI is the synthase of 3OH-C14:1-HSL and cinR is the receptor of 3OH-C14:1-HSL. CinI is a typical LuxI-type synthase, and cinR is a LuxR-type transcriptional regulator. Pcin is activated by CinR binding with 3OH-C14:1-HSL.