STUDIES OF VIABLE T4-BACTERIOPHAGE CONTAINING CYTOSINE-SUBSTITUTED DNA (T4DC-PHAGE) .2. CLEAVAGE OF T4DC DNA BY ENDONUCLEASE SALI AND BAMHI

Digestion of non-glucosylated and cytosine-substituted T4 phage (T4dC) DNA with SalI restriction endonuclease showed that the DNA had nine SalI-sensitive sites. There were eight SalI sites in DNA from a strain which had a deletion in the rII-denB-ndd region. The comparison of two digestion patterns indicated that one of the SalI-sensitive sites was present in the deleted region and that the SalI-F fragment (8.4x106 daltons) was located adjacent to the SalI-C or SalI-D fragment (15.5x106 daltons) on the T4 chromosome. The DNA gave no detectable cleavage product when digested with BamHI endonuclease alone, while, when digested successively with BamHI and SalI, the DNA yielded two new digestion products in place of one fragment formed by SalI alone. The BamHI-sensitive site was in the SalI-A fragment (25.2x106 daltons). The usefulness of this information for making cleavage maps of T4 phage chromosome is discussed. © 1979 Springer-Verlag.