Regulation of damage-inducible genes in Escherichia coli☆

Abstract The expression of the dinA , dinB , dinD and dinF genes of Escherichia coli is stimulated by certain agents that either damage DNA or block DNA replication. These agents induce the complex SOS response. Genetic evidence is presented to show that the expression of each of these genes is blocked in uninduced cells by the same repressor, the lexA protein. In addition, the regulatory regions of the dinA and dinB genes were cloned, and the approximate positions of the promoters were determined. Purified lexA protein was found to block transcription of these genes in vitro .