PHYSICAL AND GENETIC CHARACTERIZATIONS OF CLONED FRAGMENTS OF BACILLUS SUBTILIS BACTERIOPHAGE SP01 DNA (HYDROXYMETHYL URACIL, THYMINE, HOST-KILLING)
CURRAN, JAMES FREDERICK
Doctor of Philosophy
Bacillus subtilis bacteriophage SP01 causes pleiotrophic cessations of host metabolism and kills the host. Nonetheless, a large number of restriction fragments, representing approximately two thirds of the genome, can be maintained as cloned fragments in the natural host. Several fragments, which were not easily cloned, contain genes that are detrimental to bacterial hosts. The clones are convenient sources of specific SP01 fragments for use in restriction mapping and were used to map the Xba I sites in the SP01 genome. Specific genes can be identified on cloned fragments by interactions between phage mutants and cloned fragments during infection. Most of the known genes were located on specific fragments, and this information was used to refine the correlation between the physical and genetic maps of SP01. SP01 DNA contains a thymine analog, hydroxymethyl uracil. Cloned fragments contain thymine, even during SP01 infection, yet cloned DNA is active in expression of its genetic information and in recombination with superinfecting SP01 DNA. These results argue that hydroxymethyl uracil is not strictly required for those activities.