Fig. 1From: TetR-family transcription factors in Gram-negative bacteria: conservation, variation and implications for efflux-mediated antimicrobial resistanceTFTR regulation classification proposed by Ahn et al. Current classification system of TFTRs as proposed by Ahn et al. Type I classification involves the TFTR gene regulating a divergently expressed target gene (i.e. AcrR). Type II TFTRs regulate genes directly up/downstream in the same orientation (i.e. ComR). Type III TFTRs regulate genes either up/downstream of the TFTR gene in any orientation and any location on the genomeBack to article page