Quorum sensing (QS), a phenomenon of microbial intercellular signaling, has encouraged efforts to counter biofilm-based pathogenicity, for instance, through QS targeted inhibition and analog-based quorum quenching.  Moreover, these well-defined gene networks have been exploited for genetically engineered applications, such as for population-wide artificial cell responses and even synthetically mimicking the signal.  For example, our previous work has engineered protein assemblies which enzymatically generate autoinducer-2 (AI-2), a QS signaling molecule, in vitro.  Here, this fusion protein has achieved further versatility: coupling the event of DNA methylation as a precursor step creates an opportunity for sequence-encoded programmability in the reaction pathway.  That is, �templating� substrate DNA- designating particular sequences for methylation- influences the extent of AI-2 production. Combining the reactions occurs through a common intermediate where the byproduct of DNA methylation, S-adenosylhomocysteine (SAH) also doubles as a substrate for AI-2 synthesis; their coupling advantageously imparts control into the generation of an AI-2 signal. Our AI-2 synthesis chain reaction has been incorporated into a physical system by encapsulating the components using biopolymers, thereby �biofabricating� a single entity that can act as an artificial signal source.  The �bioactive� capsule can then be transplanted into a relevant environment, one where it can participate in quorum sensing signaling, and thereby elicit communication-based interactions with bacteria that have been engineered as reporters of AI-2. This work exploits the root power of synthetic biology - engineering DNA � using quorum sensing inspiration to construct an entirely new function: the direct DNA-based programming of biochemical flux. That is, we have �templated� the production of a small molecule (AI-2) that, in turn, will dynamically coordinate populations of cells to meet specific demands. Furthermore, we have combined the power of biofabrication with that of synthetic biology to create connections between the ex and in vivo environments in ways that expand the field.

DNA methylation for encoding quorum sensing-inspired cell communication

247th National Meeting (2014)

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