INTRAGENIC SUPPRESSORS OF INDUCTION-DEFICIENT TETR MUTANTS - LOCALIZATION AND POTENTIAL MECHANISM OF ACTION

Eight Tn10 Tet repressor mutants with an induction-deficient phenotype and with primary mutations located at or close to the dimer interface were mutagenized and screened for inducibility in the presence of tet racycline, The second-site suppressors with wild-type-like operator bi nding activity that were obtained act, except for one, at a distance, suggesting that they contribute to conformational changes in the Tet r epressor. Many of these long-range suppressors occur along the dimer i nterface, indicating that interactions between the monomers play an im portant role in Tet repressor induction.