Cleavage maps of the filamentous bacteriophages M13, fd, fl, and ZJ/2.

The replicative form DNAs of bacteriophage M13, fd, f1, and ZJ/2 were found to be sensitive to cleavage by the restriction endonucleases endoR-HapII, endoR-HaeII, endoR-HaeIII, endoR-HindII, endoR-AluI, endoR-Hha, and endoR-Hinf. With respect to M13 DNA the number of cleavage sites varied from 21 for endoR-Hinf, 18 for endoR-AluI, 15 for endoR-Hha, 13 for endoR-HapII, 10 for endoR-HaeIII, 3 for endoR-HaeII, to only a single site for endoR-HindII. In contrast to M13, fd and f1, the ZJ/2 DNA molecule was not cleaved by the endoR-HindII endonuclease. No cleavage site on either phage DNA was detected for the endonucleases endoR-Hsu, endoR-EcoRI and endoR-Sma. When compared with M13 DNA, several differences were noted in the number and size of cleavage products obtained with DNA of phage fd, f1, and ZJ/2. From the results of these analyses, using the M13 enzyme cleavage maps as a reference, the endoR-HapII, endoR-HaeII, endoR-HaeIII, endoR-HindII and endoR-AluI maps of phage fd, f1, and ZJ/2 could be constructed. As is expected for very closely related phages, the enzyme cleavage patterns exhibit a high degree of homology. Phage f1 and ZJ/2 are most related since an identical pattern was obtained with seven different restriction endonucleases. Evidence is provided also that f1 is more similar to M13 than to fd. Furthermore, characteristic differences exist within the endoR-Hinf enzyme cleavage pattern of all the four phages tested. Digestion of phage DNA with this enzyme, therefore, provides a new and sensitive method of distinguishing these closely related filamentous coliphages .