AHLs, (N-acylhomoserine lactones), known as autoinducers (AIs), are widely conserved signal molecules present in quorum-sensing systems of many gram-negative bacteria. The conservation and potent activity of these signaling molecules is based on the lactone ring. LuxR,is a protein that can bind AHL. When bound to AHL it can stimulate transcription by binding to LuxR binding sites of the lux promoter (pLux). The well studied operon of the pLux promoter is originally isolated from the bacterium Vibrio fischeri. . The tet promoter is constitutively active and can be repressed by the transcriptional regulator TetR. In turn, TetR repression is inhibited by the addition of tetracycline. In 2015, the HS iGEM team generated and tested the part BBa_K1767010 that is based on this exsting BioBrick (see experience).
