Table 1 Proposed biological roles of TFTRs of Salmonella and Escherichia. TFTRs present in all Gram-negative species tested are denoted as core**, while those not present in all species but present in all Escherichia and Salmonella are denoted as core*. The carriage of the remaining TFTRs found in Salmonella and Escherichia are listed (%, italicised for Salmonella). This data is combined with biological role as documented in literature. Known targets and ligands are included and targets known to be activated, not repressed, by the TFTR are in bold. A biological role was assigned from the literature if experimental evidence was provided (e.g. binding assays to show TFTR binding to promoter)
TFTR | Core/Accessory (%) | Pathway | Gene(s) or process regulated (organism) | Ligands | References |
|---|---|---|---|---|---|
AcrR | Core** | Multidrug efflux (RND) Multidrug efflux (ABC) Multidrug efflux (MFS) Motility | acrAB (Enterobacteriales) flhDC | Rhodamine 6 g Proflavin Ethidium bromide Ciprofloxacin | [19] [20] [21] |
EnvR | Core** | Multidrug efflux (RND) Multidrug efflux (RND) | acrAB (Enterobacteriales) acrEF (Enterobacteriales) | No data available | [9] |
NemR | Core** | Bleach survival | nemAB | Choline | [22] |
SlmA | Core* | Cell division Chitin catabolism | FtsZ ring formation(Enterobacteriales) chb operon (V. cholera) | Target DNA sequences FtsZ protein | [23] [24] [25] |
YbiH | Core* | Multidrug efflux (ABC) Membrane permeability | ybhGFSR (E. coli) rhlE(E. coli) | Chloramphenicol Cephalosporin | [26] |
BetI | Accessory (67%) | Glycine betaine synthesis | betT (Enterobacteriales) betIBA (Enterobacteriales) | Choline | [27] |
EefR | Accessory (47%) | Multidrug efflux (RND) | eefABC (Enterobacter spp., K. pneumoniae) | No data available | [28] [29] |
FabR | Core Accessory (93%) | Fatty acid biosynthesis | fabAB (Enterobacteriales) | Unsaturated thioester | [30] |
RamR | Core | Efflux regulation | ramA (Enterobacteriales) | Bile Berberine Ethidium bromide Dequalinium Crystal violet Rhodamine 6 g | [31] [32] [33] |
RutR | Core Accessory (93%) | Pyrimidine utilisation Purine degradation Glutamine supply PH homeostasis | rutABCDEFG (E. coli) carAB (E. coli) gadAXW (E. coli) gadIBC (E. coli) gly-hyi-glxR-ybbVW-allB-ybbY-glxK (E. coli) | Uracil Thymine | [34] [11] [35] |
TetR | Accessory (40%) Accessory (20%) | Multidrug efflux (ABC) | tetAB (Enterobacteriales) | Tetracycline | [36] |
UidR | Accessory (67%) | Catalysis of beta-glucuronidase | uidA (E. coli) | No data available | [37] |
U1 | Core | No data available | No data available | No data available | Â |
YbjK/ RcdA | Accessory (93%) Accessory (80%) | Biofilm formation Stress response | csgD (E. coli) appY, sxy, ycgF, fimB (E. coli) | No data available | [38] |
YcfQ/ comR | Accessory (80%) Core | Copper transport | comC (E. coli) | Copper | [39] |
YftA | Accessory (80%) | No data available | No data available | No data available | Â |
YjdC | Accessory (67%) Core | Copper tolerance | cadABC (E. coli) | No data available | [40] |
YjgJ/ bdcR | Accessory (60%) Accessory (93%) | Biofilm dispersal | bdcA (E. coli) | No data available | [41] |