A new element in the control of DNA initiation in Escherichia coli

When a thermosensitive mutant of E. coli affected in DNA initiation is heated to 41 degrees , a protein needed for DNA initiation is irreversibly denatured. When these bacteria are incubated at 30 degrees in the presence of several concentrations of chloramphenicol, DNA synthesis is greatly stimulated at a chloramphenicol, DNA synthesis is greatly stimulated at a chloramphenicol concentration of 2.5 mug/ml, and then sharply decreases. This stimulation of DNA synthesis appears to be caused by an increased frequency of initiation. The existence of an "anti-initiator" protein controlling the frequency of chromosomal initiation is proposed.