TABLE 3.
Osmoresponsive genes and operons in E. coli
| Gene or operon | Encoded function | Locus-specific transcriptional regulator(s) | Reference(s) |
|---|---|---|---|
| aqpZ | Aquaporin | 32 | |
| betTIBA | Choline uptake and oxidation | BetTa | 142 |
| kdpFABCDE | Potassium transport and transcriptional regulation | KdpD/KdpE | 2 |
| mdo | MDO synthesis | 140 | |
| ompF | Porin | EnvZ/OmpR | 255 |
| ompC | Porin | EnvZ/OmpR | 255 |
| osmB | Putative lipoprotein | 109 | |
| osmC | Putative lipoprotein | 88 | |
| osmE | Unknown | 88 | |
| osmY | Unknown | 145, 306 | |
| otsAB | Cytoplasmic trehalose synthesis | 100 | |
| proP | Compatible-solute transport | 302 | |
| proU | Compatible-solute transport | 159 (see text) | |
| stpA | Nucleoid protein | 73 | |
| treA | Periplasmic trehalose hydrolysis | 100 |
a
BetI is a repressor that modulates the transcription of betT and betIBA from divergent promoters in response to choline supply, and ArcA represses their transcription under anaerobic conditions. Osmotic induction of these loci is independent of BetI, H-NS and RpoS, however (142).