Proof of concept continuous event logging in living cells

Title	Proof of concept continuous event logging in living cells
Authors	Andrey Shur and Richard M Murray
Source	2018 Synthetic Biology: Engineering, Evolution and Design (SEED) Conference
Abstract	Biological records are omnipresent in paleontology, history, and climate science. Tree rings and ice cores provide evidence of environmental conditions that have been recorded in the composition of materials that are deposited over time, carrying with them a record of events that have influenced their existence before being buried underneath ice or inside the trunk of a tree. We constructed a proof of concept synthetic circuit that can be used to create a similar chronological record of events in the DNA of a living E. coli. In our system, phage-based serine integrases are employed to sequentially integrate pieces of DNA corresponding to which stimulus is being detected. We show that placing attB and attP sites close together on a piece of DNA prevents intramolecular reactions, and enables repeated integration events to expand a genetic locus proportionally to integrase induction and abundance of plasmid DNA. We also show that dCas9 binding can prevent integrase from reacting with an attachment site, and in so doing we can control which piece of DNA is integrated by the induction of different guide RNAs. These results represent significant steps towards an event logger that is capable of recording the ordering and magnitude of any number of molecular events. Such a system may be useful in studying complex biological phenomena such as biofilm formation, quorum sensing, or signaling in the gut.
Type	Conference paper
URL	https://www.biorxiv.org/content/early/2018/03/08/225151
DOI
Tag	sm18-seed
ID	2018a
Funding	DARPA BioCon
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