title: The ori of filamentous phage phi Lf is located within the gene encoding the replication initiation protein.
abstract: phi Lf is a filamentous phage of Xanthomonas campestris pv. campestris. In this study, the origin for phi Lf replication was located in a 121-bp TaqI fragment within gII, the gene encoding the replication initiation protein. This fragment, ligating with a GmR catridge, was able to be maintained as a plasmid (pT2) in strain Xc17 with the gII being provided in trans. ssDNA of pT2 was detected in the cells, indicating that pT2 may replicate by a rolling circle replication mechanism. Upon superinfection of Xc17 containing pT2 with phi Lf, transducing particles containing ssDNA of pT2 were released, suggesting the presence of packaging signal in the 121-bp TaqI fragment. This fragment contains a sequence homologous to the nicking sites for superfamily I Rep proteins of the rolling circle-replicating replicons, in concert with the presence of conserved amino acid sequence motifs of the superfamily I Rep proteins in the phi Lf gIIP.
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: N T
authors.initials: NT
authors.lastname: Lin
authors.forename: Y H
authors.initials: YH
authors.lastname: Tseng
mesh_terms: D001435:Bacteriophages / Q000235:genetics*; D001483:Base Sequence; D004275:DNA, Ribosomal / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000032:analysis / Q000378:metabolism; D004279:DNA, Viral / Q000302:isolation & purification / Q000378:metabolism; D005814:Genes, Viral; D008969:Molecular Sequence Data; D018741:Replication Origin; D012093:Replicon; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics*; D016959:Xanthomonas campestris / Q000821:virology*
chemical_list: D004275:DNA, Ribosomal; D004277:DNA, Single-Stranded; D004279:DNA, Viral; C102376:GII protein, Xanthomonas campestris phage phi-Lf; D014764:Viral Proteins