Targeted and autonomous communication of arbitrary DNA messages via a reusable cell-cell communication channel. (a) Bacteriophage M13-based cell-cell communication was used to send a DNA message, “GFP and ampicillin resistance”, to receiver cells constitutively expressing mKate2. Schematic shows expected locations of cell populations after flow cytometry analysis. Data show fluorescence of GFP and mKate2 of co-cultures at the start of an experiment (t = 0) and after co-culture without antibiotic selection (t = 5 hr). Data are shown for experiments using cells with varying attributes, listed to the right of each pair of plots. (b) Schematic showing sender and receiver genotypes and expected message transmission of a lock-and-key system. Sender cells contain and transmit “T7 RNA polymerase autogene.” Receivers contain a green fluorescent protein-lacZ alpha fragment fusion (“Gemini”) under the control of a T7 promoter. Expression of Gemini is unlocked in Receivers given message transmission (34). (c) Communication of a lock-and-key message demonstrating decoupling and also the capacity for specificity of decoding received messages. Percentage of maximum events as a function of GFP fluorescence are shown for sender cells (XL1-Blue, Litmus-T7 RNA polymerase), receiver cells (XL1-Blue, pSB4C5-T7promoter-Gemini), co-cultures of receiver and sender cells, and a positive control (XL1-Blue, co-transformed with Litmus-T7 RNA polymerase and pSB4C5-T7promoter-Gemini). The curves for co-culture fluorescence are pooled data from three separate co-culture flasks. Data are shown for the start of the experiment (t = 0) and after selection with antibiotics (post-selection). Additional transmitted messages (Additional file 1: Figure S6).