Light-programmable Logic Gate

This paper describes a new method of retroactively programming a genetic circuit to exhibit the behavior of one of four logic gates (AND, OR, NAND, and NOR) using pulses of light. These pulses must occur after DNA transfection into the host cell. The pulses of light deactivate a photosensitive kinase, inhibiting phosphorylation. Using this effect, we can control the transcription of recombinase enzymes that can ”reprogram” our DNA-based circuits through excision of particular sections of DNA, as determined through placement of recombination sites. We also describe a novel circuit design for an ”undifferentiated logic gate” that can be reduced to any of the four basic logic gates through the introduction of reecombinase to the system.