Figure 2.

Illustration of CFE phenomena, including plasmid crosstalk, and hypotheses about their underlying causes. Cell-free expression increases with increasing plasmid concentration in low concentration regimes, but as the concentration of plasmid gets very high, total expression decreases; this phenomenon is hypothesized to be due to macromolecular crowding or toxins produced from translation. When multiple different plasmids are added, they compete for various resources (e.g. polymerases or nucleases), causing the expression to be higher or lower than the baseline depending on whether the resources lead to production or degradation of the gene product. These hypotheses were integrated into a computational model.