Effect of DNA supercoiling and catabolite repression on the expression of the tetA genes in Escherichia coli

Abstract
The effect of novobiocin, a gyrase inhibitor, and of catabolite repression on the expression of different classes of tetA genes in Escherichia coli was studied. The results obtained showed that the complete induction of the tetA genes corresponding to classes A, B, and D depends on DNA supercoiling, and that the expression of the tetA genes corresponding to classes A and C is not under catabolite repression.