title: Implementing an OR-NOT (ORN) logic gate with components of the SOS regulatory network of Escherichia coli.
abstract: Whether biological or electronic, man-engineered computation is based on logic circuits assembled with binary gates that are interconnected to perform Boolean operations. We report here the rewiring of the SOS system of Escherichia in a fashion that makes the output of both the recA and lexA promoters to faithfully follow the pattern of a binary composite OR-NOT gate (ORN) in which the inputs are DNA damage (e.g. nalidixic acid addition) and IPTG as an exogenous signal. Unlike other non-natural gates whose implementation requires changes in genes and promoters of the genome of the host cells, this ORN was brought about by the sole addition of wild-type bacteria with a plasmid encoding a module for LacI(q)-dependent expression of lexA. Specifically, we demonstrate that the interplay between native, chromosomally-encoded components of the SOS system and the extra parts engineered in such a plasmid made the desired performance to happen without any modification of the core DNA-damage response network. It is thus possible to artificially interface autonomous cell networks with a predetermined logic by means of Boolean gates built with regulatory elements already functioning in the recipient organism.
authors.affiliation: Systems and Synthetic Biology Program, Centro Nacional de Biotecnología CSIC, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Silva-Rocha
authors.forename: Víctor
authors.initials: V
authors.lastname: de Lorenzo
mesh_terms: D001185:Artificial Intelligence; D001426:Bacterial Proteins / Q000235:genetics; D004249:DNA Damage; D004926:Escherichia coli / Q000235:genetics*; D053263:Gene Regulatory Networks; D049452:Green Fluorescent Proteins / Q000235:genetics; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D008128:Logic; D008957:Models, Genetic; D009268:Nalidixic Acid / Q000494:pharmacology; D050436:Regulatory Elements, Transcriptional; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases / Q000235:genetics; D015398:Signal Transduction; D049490:Systems Biology; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D049452:Green Fluorescent Proteins; D007544:Isopropyl Thiogalactoside; D009268:Nalidixic Acid; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein