title: Structure and regulation of the lytic replicon of phage P1.
abstract: Three replicons, R, L and P1dR, have been previously identified in bacteriophage P1, but only the R (or plasmid) replicon has been functionally and structurally characterized. Evidence is provided here that the L-replicon is the principal replicon used for DNA replication during the lytic cycle. The L-replicon (exclusive of its promoter) is shown to be contained within a 1093-base-pair DNA segment that includes a 281-codon open reading frame, designated repL. L-replicon function requires transcription in the direction that should generate translatable repL message. This transcription is normally under the control of the phage c1 repressor, but a deletion that places the functional L-replicon under alternative control can be constructed. The DNA sequence of the replicon and surrounding regions was established. The sequenced region contains the c4 and ant genes and a hitherto unidentified gene, kilA, which is immediately upstream of repL and is controlled by the c1-regulated promoter. The kilA gene was shown to be non-essential for both replication and lytic development whereas the repL gene probably encodes an essential replication protein.
authors.affiliation: Laboratory of Biochemistry, National Cancer Institute, Bethesda, MD 20892.
authors.forename: E B
authors.initials: EB
authors.lastname: Hansen
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics*; D004261:DNA Replication; D004279:DNA, Viral / Q000235:genetics; D004926:Escherichia coli; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D012093:Replicon; D015183:Restriction Mapping; D014779:Virus Replication
chemical_list: D004279:DNA, Viral