Evidence for a new endonuclease synthesized by lambda bacteriophage.
Infection of nonlysogenic Escherichia coli CR34(S) (Thy(-)) with bacteriophage lambda C(I)857 resulted in the formation of twisted circular double-stranded phage deoxyribonucleic acid (DNA; species I). When such infected bacteria were incubated in the absence of thymine, there was a significant decrease in the amount of species I DNA after 60 min of incubation. A similar loss of species I lambda DNA during incubation in a thymine-deficient medium was also observed after infection of the endonuclease I-deficient strain, E. coli 1100(S) (Thy(-)). This destruction of twisted, circular lambda DNA in thymine-deprived cells did not occur in the presence of chloramphenicol nor in lysogenic E. coli CR34 carrying a noninducible lambda prophage. It is therefore concluded that the endonuclease which attacks this circular configuration of lambda DNA is newly synthesized after infection and is directed by the phage chromosome.
D002501:Centrifugation, Zonal; D002701:Chloramphenicol / Q000494:pharmacology; D003090:Coliphages / Q000201:enzymology*; D004279:DNA, Viral / Q000096:biosynthesis / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000096:biosynthesis*; D009154:Mutation; D013941:Thymine / Q000494:pharmacology; D014316:Tritium
D004279:DNA, Viral; D014316:Tritium; D002701:Chloramphenicol; D003851:Deoxyribonucleases; D013941:Thymine