title: Degradation of Escherichia coli B deoxyribonucleic acid after infection with deoxyribonucleic acid-defective amber mutants of bacteriophage T7.
abstract: The degradation of bacterial deoxyribonucleic acid (DNA) was studied after infection of Escherichia coli B with DNA-negative amber mutants of bacteriophage T7. Degradation occurred in three stages. (i) Release of the DNA from a rapidly sedimenting cellular structure occurred between 5 and 6 min after infection. (ii) The DNA was cleaved endonucleolytically to fragments having a molecular weight of about 2 x 10(6) between 6 and 10 min after infection. (iii) These fragments of DNA were reduced to acid-soluble products between 7.5 and 15 min after infection. Stage 1 did not occur in the absence of the gene 1 product (ribonucleic acid polymerase sigma factor), stage 2 did not occur in the absence of the gene 3 product (phage T7-induced endonuclease), and stage 3 did not occur in the absence of the gene 6 product.
mesh_terms: D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D011232:Chemical Precipitation; D003090:Coliphages / Q000201:enzymology / Q000254:growth & development*; D004269:DNA, Bacterial / Q000032:analysis / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D003902:Detergents; D004926:Escherichia coli / Q000032:analysis / Q000378:metabolism*; D005796:Genes; D005827:Genetics, Microbial; D009154:Mutation; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D012965:Sodium Chloride; D013395:Sucrose; D013936:Thymidine / Q000378:metabolism; D013941:Thymine / Q000378:metabolism; D014238:Trichloroacetic Acid; D014316:Tritium
chemical_list: D002247:Carbon Isotopes; D004269:DNA, Bacterial; D003902:Detergents; D014316:Tritium; D012965:Sodium Chloride; D013395:Sucrose; D014238:Trichloroacetic Acid; D012316:RNA Nucleotidyltransferases; D003851:Deoxyribonucleases; D013941:Thymine; D013936:Thymidine