Open AccessA fourth class of theta-replicating plasmids: the pAM beta 1 family from gram-positive bacteria.
Author(s) -
Claude Bruand,
Emmanuelle Le Chatelier,
S. Dusko Ehrlich,
Laurent Jannière
Publication year - 1993
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.90.24.11668
Subject(s) - replicon , plasmid , biology , cole1 , rolling circle replication , genetics , dna replication , homology (biology) , origin of replication , encode , dna , microbiology and biotechnology , gene
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.