Open AccessEnvironmental signal integration by a modular AND gate
Author(s) -
Anderson J Christopher,
Voigt Christopher A,
Arkin Adam P
Publication year - 2007
Publication title -
molecular systems biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.523
H-Index - 148
ISSN - 1744-4292
DOI - 10.1038/msb4100173
Subject(s) - biology , promoter , synthetic biology , t7 rna polymerase , transcription (linguistics) , modular design , computational biology , sigma factor , genetics , modularity (biology) , transfer rna , rna polymerase iii , rna polymerase , gene , rna , escherichia coli , computer science , gene expression , operating system , linguistics , philosophy , bacteriophage
Microorganisms use genetic circuits to integrate environmental information. We have constructed a synthetic AND gate in the bacterium Escherichia coli that integrates information from two promoters as inputs and activates a promoter output only when both input promoters are transcriptionally active. The integration occurs via an interaction between an mRNA and tRNA. The first promoter controls the transcription of a T7 RNA polymerase gene with two internal amber stop codons blocking translation. The second promoter controls the amber suppressor tRNA supD . When both components are transcribed, T7 RNA polymerase is synthesized and this in turn activates a T7 promoter. Because inputs and outputs are promoters, the design is modular; that is, it can be reconnected to integrate different input signals and the output can be used to drive different cellular responses. We demonstrate this modularity by wiring the gate to integrate natural promoters (responding to Mg 2+ and AI‐1) and using it to implement a phenotypic output (invasion of mammalian cells). A mathematical model of the transfer function is derived and parameterized using experimental data.