With J. L. Rosner and M. B. Yarmolinsky, Cold Spring Harbor Symposia on Quantitative Biology 33:785-789, 1968.
Induction of lysogenic bacteria may be accomplished by a variety of means, all of which involve the loss or inactivation of a prophage-specific system of repression. Thus, in zygotic induction the prophage is freed from its repressor by transfer to a cellular environment where repressor is absent. In thermal induction, prophage bearing particular mutations in the repressor-determining gene are induced by direct inactivation of the repressor (Sussman and Jacob, 1962). Induction by certain physical and chemical treatments (e.g., irradiation with ultraviolet light or X-rays, exposure to mitomycin C, or transient deprivation of thymine), all of which interfere with bacterial DNA synthesis, is more complex and, in each case tested, requires the product of the bacterial recA gene (Brooks and Clark, 1967; Hertman and Luria, 1967). Although these treatments do not act directly on the repressor molecule (Tomizawa and Ogawa, 1967), they must ultimately induce by releasing the prophage repression system.