RT Journal Article SR Electronic(1) A1 Shimizu-Kadota, Mariko A1 Tsuchida, NobuoYR 1984 T1 Physical Mapping of the Virion and the Prophage DNAs of a Temperate Lactobacillus phage øFSW JF Microbiology, VO 130 IS 2 SP 423 OP 430 DO https://doi.org/10.1099/00221287-130-2-423 PB Microbiology Society, SN 1465-2080, AB We analysed the physical structure of the DNA of øFSW, which is a temperate phage of Lactobacillus casei S-1. A circular restriction map of the virion DNA has been constructed with three restriction endonucleases, BamHI, SalI and XhoI. Other data indicated that the phage genome was circularly permuted. In lysogens, the DNA of the prophage was found to be linearized at a specific site and integrated into a specific locus of the host genome, with the same orientation in each case, as evidenced by Southern filter hybridization. We compared the physical structure of øFSW with its three virulent mutants. One of them had a restriction map indistinguishable from that of øFSW and two of them contained host-derived DNA sequence(s) in a specific region of the øFSW genome (V-region). The prophage integration site was mapped on a different segment of the phage genome to the V-region. Derivation of virulent mutants from øFSW is discussed in relation to the physical structure of the phage genome., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-130-2-423