title: A fourth class of theta-replicating plasmids: the pAM beta 1 family from gram-positive bacteria.
abstract: Plasmid pAM beta 1 from Enterococcus faecalis uses a unidirectional theta mode of replication. We show here that this replication (i) is dependent on a plasmid-encoded replication protein (Rep) but not on a DNA structure typical for origins of most Rep-dependent plasmids and (ii) is initiated by DNA polymerase I (PolI). pAM beta 1 minimal replicon shares no homology with highly conserved ColE1-type replicons, which use PolI for initiation but do not encode a Rep, or with ColE2 and ColE3 replicons, which require PolI for replication and encode a Rep. We propose that pAM beta 1 and a number of other naturally occurring and closely related plasmids from a distinct plasmid class.
authors.affiliation: Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, Jouy en Josas, France.
authors.forename: C
authors.initials: C
authors.lastname: Bruand
authors.forename: E
authors.initials: E
authors.lastname: Le Chatelier
authors.forename: S D
authors.initials: SD
authors.lastname: Ehrlich
authors.forename: L
authors.initials: L
authors.lastname: Jannière
mesh_terms: D001483:Base Sequence; D017124:Conserved Sequence; D004256:DNA Polymerase I / Q000378:metabolism; D017931:DNA Primers; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D013293:Enterococcus faecalis / Q000235:genetics*; D029968:Escherichia coli Proteins; D006094:Gram-Positive Bacteria / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012093:Replicon; D012097:Repressor Proteins / Q000096:biosynthesis / Q000378:metabolism*; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013698:Templates, Genetic
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C074164:RepE protein, E coli; D012097:Repressor Proteins; D004256:DNA Polymerase I