title: Bacteriophage T4 initiates bidirectional DNA replication through a two-step process.
abstract: Two-dimensional gel analysis of the bacteriophage T4 ori(uvsY) region revealed a novel "comet" on the Y arc. This comet contains simple Y molecules in which the branch points map to the ori(uvsY) transcript region. The comet depends on the the origin and DNA synthesis and is abolished by a mutation that reduces replication without affecting transcription. These results argue that the branched molecules are intermediates in replication initiation. A transcriptional terminator, cloned just downstream of the origin promoter, shortened the tail of the comet. Therefore, the location of the transcript determines the DNA branch points. We conclude that the comet DNA consists of intermediates in which unidirectional replication has been triggered by priming from the RNA of the origin R loop.
authors.affiliation: Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: K G
authors.initials: KG
authors.lastname: Belanger
authors.forename: K N
authors.initials: KN
authors.lastname: Kreuzer
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics / Q000502:physiology*; D015152:Blotting, Northern; D015139:Blotting, Southern; D004265:DNA Helicases / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics / Q000502:physiology*; D004279:DNA, Viral / Q000096:biosynthesis / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D004259:DNA-Directed DNA Polymerase; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000821:virology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D009154:Mutation; D020161:Physical Chromosome Mapping; D012367:RNA, Viral / Q000378:metabolism; D011995:Recombination, Genetic / Q000502:physiology; D018741:Replication Origin / Q000235:genetics / Q000502:physiology*; D016914:Ribonuclease H / Q000235:genetics / Q000502:physiology; D013728:Terminator Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic / Q000502:physiology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014779:Virus Replication / Q000235:genetics / Q000502:physiology*
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D012367:RNA, Viral; C092863:UvsX protein, Enterobacteria phage T4; C092864:UvsY protein, Enterobacteria phage T4; D014764:Viral Proteins; C069983:gene 43 protein, Enterobacteria phage T4; D004259:DNA-Directed DNA Polymerase; D016914:Ribonuclease H; D004265:DNA Helicases