title: Isolation and characterization of the replicon of a Thiobacillus intermedius plasmid.
abstract: The replicon of a cryptic Thiobacillus intermedius plasmid (pTiK12) has been isolated and sequenced. Functional analysis of deletion subclones in Escherichia coli localized the replicon to a 3.5-kb region of DNA. Sequencing of this region identified a 30-bp A-T-rich potential stem-loop structure. In addition, an 11-bp direct repeat, an 11-bp inverted repeat, and a 16-bp inverted repeat were observed at the stem-loop structure. Also found in the replicon was a series of four tandem direct repeats consisting of a perfectly conserved 8-bp core. A region near the stem-loop structure is involved in the regulation of plasmid copy number. Deletion subclones lacking this region have increased copy numbers, indicating a negative regulatory role. An open reading frame capable of encoding a 320-amino-acid protein was found near the stem-loop structure. The putative amino acid sequence shares significant similarity with the two Rep proteins from the ColE2 and ColE3 replicons. Replication of the T. intermedius replicon is dependent upon DNA polymerase I. The isolation and examination of the T. intermedius plasmid replicon are initial steps toward the establishment of a genetic system in T. intermedius.
authors.affiliation: Department of Biological Sciences, Clemson University, South Carolina 29634-1903, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: English
authors.forename: S C
authors.initials: SC
authors.lastname: Lorbach
authors.forename: K M
authors.initials: KM
authors.lastname: Huffman
authors.forename: J M
authors.initials: JM
authors.lastname: Shively
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry; D001483:Base Sequence; D003001:Cloning, Molecular; D003087:Colicins / Q000737:chemistry; D017124:Conserved Sequence; D004265:DNA Helicases; D004256:DNA Polymerase I; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004268:DNA-Binding Proteins; D004926:Escherichia coli; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010448:Peptide Initiation Factors / Q000096:biosynthesis* / Q000737:chemistry; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D012093:Replicon; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013855:Thiobacillus / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D003087:Colicins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D010448:Peptide Initiation Factors; D015534:Trans-Activators; C045264:replication initiator protein; D004256:DNA Polymerase I; D004265:DNA Helicases