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Characterization of a theta plasmid replicon with homology to all four large plasmids of Bacillus megaterium QM B1551. Plasmid 1998 Nov;40(3):175-89

Date

11/10/1998

Pubmed ID

9806855

DOI

10.1006/plas.1998.1359

Scopus ID

2-s2.0-0031792623 (requires institutional sign-in at Scopus site)   12 Citations

Abstract

A replicon from one of an array of seven indigenous compatible plasmids of Bacillus megaterium QM B1551 has been cloned and sequenced. The replicon hybridized with all four of the large plasmids (165, 108, 71, and 47 kb) of strain QM B1551. The cloned 2374-bp HindIII fragment was sequenced and contained two upstream palindromes and a large (>419-amino-acid) open reading frame (ORF) truncated at the 3' end. Unlike most plasmid origins, a region of four tandem 12-bp direct repeats was located within the ORF. The direct repeats alone were incompatible with the replicon, suggesting that they are iterons and that the plasmid probably replicates by theta replication. The ORF product was shown to act in trans. A small region with similarity to the B. subtilis chromosomal origin membrane binding region was detected as were possible binding sites for DnaA and IHF proteins. Deletion analysis showed the minimal replicon to be a 1675-bp fragment containing the incomplete ORF plus 536 bp upstream. The predicted ORF protein of >48 kDa was basic and rich in glutamate + glutamine (16%). There was no significant amino acid similarity to any gene, nor were there any obvious motifs present in the ORF. The data suggest that this is a theta replicon with an expressed rep gene required for replication. The replicon contains its iterons within the gene and has no homology to reported replicons. It is the first characterization of a B. megaterium replicon.

Author List

Stevenson DM, Kunnimalaiyaan M, Müller K, Vary PS

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Bacillus megaterium
Bacillus subtilis
Bacterial Proteins
Base Sequence
Cloning, Molecular
DNA Polymerase I
DNA Replication
DNA, Bacterial
Gene Library
Genetic Complementation Test
Molecular Sequence Data
Open Reading Frames
Plasmids
Rec A Recombinases
Repetitive Sequences, Nucleic Acid
Replicon
Sequence Alignment
Sequence Analysis, DNA
Sequence Deletion
Sequence Homology
Sequence Homology, Nucleic Acid
Species Specificity
Spores, Bacterial
Transformation, Bacterial