Endogenous eukaryotic signals that stimulate synthetic sensors
| Input signal | Synthetic sensor | Sensor function |
| Estrogen | ATF: Gal4 (DBD), estrogen receptor (TAD) (Webster et al., 1988; Braselmann et al., 1993) | Transcription activation at the Gal4 element |
| Hypoxia | ATF: Gal4 (DBD), HIF-1α oxygen-dependent degradation domain, p65 (TAD) (Tang et al., 2005) | Transcription activation at the Gal4 element |
| l-arginine synthesis | ATF: ArgR (DBD), VP16 (TAD) (Hartenbach et al., 2007) | Transcription activation at the ARG box element |
| NADH depletion (low nutrient levels) | ATF: REX (DBD), VP16 (TAD) (Weber et al., 2006) | Transcription activation at the ROP element |
| Thiamine pyrophosphate | Riboswitch: thiamine pyrophosphate (TPP) aptamer (Nomura and Yokobayashi, 2007; Yamauchi et al., 2008; Wieland et al., 2009) | Translation control via mRNA cleavage |
| Input signal | Synthetic sensor | Sensor function |
| Estrogen | ATF: Gal4 (DBD), estrogen receptor (TAD) (Webster et al., 1988; Braselmann et al., 1993) | Transcription activation at the Gal4 element |
| Hypoxia | ATF: Gal4 (DBD), HIF-1α oxygen-dependent degradation domain, p65 (TAD) (Tang et al., 2005) | Transcription activation at the Gal4 element |
| l-arginine synthesis | ATF: ArgR (DBD), VP16 (TAD) (Hartenbach et al., 2007) | Transcription activation at the ARG box element |
| NADH depletion (low nutrient levels) | ATF: REX (DBD), VP16 (TAD) (Weber et al., 2006) | Transcription activation at the ROP element |
| Thiamine pyrophosphate | Riboswitch: thiamine pyrophosphate (TPP) aptamer (Nomura and Yokobayashi, 2007; Yamauchi et al., 2008; Wieland et al., 2009) | Translation control via mRNA cleavage |
Artificial transcription factor (ATF) fusion proteins and a synthetic riboswitch are described here. DBD = DNA binding domain; TAD = transcription activation domain.