A fourth class of theta-replicating plasmids: the pAM beta 1 family from gram-positive bacteria

Proc Natl Acad Sci U S A. 1993 Dec 15;90(24):11668-72. doi: 10.1073/pnas.90.24.11668.

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Conserved Sequence
  • DNA Polymerase I / metabolism
  • DNA Primers
  • DNA Replication*
  • DNA, Bacterial / biosynthesis
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / metabolism*
  • Enterococcus faecalis / genetics*
  • Escherichia coli Proteins*
  • Gram-Positive Bacteria / genetics*
  • Molecular Sequence Data
  • Open Reading Frames
  • Plasmids*
  • Promoter Regions, Genetic
  • Replicon*
  • Repressor Proteins / biosynthesis
  • Repressor Proteins / metabolism*
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Templates, Genetic

Substances

  • DNA Primers
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • RepE protein, E coli
  • Repressor Proteins
  • DNA Polymerase I