Linear plasmids and chromosomes in bacteria

  title={Linear plasmids and chromosomes in bacteria},
  author={Joseph Hinnebusch and Kit Tilly},
  journal={Molecular Microbiology},
Linear plasmids and chromosomes were unknown in prokaryotes until recently but have now been found in spirochaetes, Gram‐positive bacteria, and Gram‐negative bacteria. Two structural types of bacterial linear DNA have been characterized. Linear plasmids of the spirochaete Borrelia have a covalently closed hairpin loop at each end and linear plasmids of the Gram‐positive filamentous Streptomyces have a covalently attached protein at each end. Replicons with similar structures are more frequent… 

Bacterial plasmids: replication of extrachromosomal genetic elements encoding resistance to antimicrobial compounds.

Plasmids are self-replicating extrachromosomal DNA molecules found in Gram-negative and Gram-positive bacteria as well as in some yeast and other fungi that encode a wide variety of genetic determinants, which permit their bacterial hosts to survive better in an adverse environment or to compete better with other microorganisms occupying the same ecological niche.

Prokaryotic and Mitochondrial Linear Genomes: Their Genesis, Evolutionary Significance, and the Problem of Replicating Chromosome Ends

This review discusses theories concerning the evolution of linear genomes and supporting experiments and the most common mechanisms of linear bacterial genomes replication and possible ways of their emergence are considered.

Replication of Linear Bacterial Chromosomes: No Longer Going Around in Circles

The linear replicons of Borrelia and Streptomyces, despite their identical topology, appear to be highly diversified in their structures and modes of replication.

A new beginning with new ends: linearisation of circular chromosomes during bacterial evolution.

Bacterial circular chromosomes have sporadically become linearised during prokaryote evolution and may contain telomere-linked regions of enhanced genomic plasticity, which undergo more frequent genetic exchanges and rearrangements and allow differential evolution of genes, depending on their chromosome location.

The Sequence of a 1.8-Mb Bacterial Linear Plasmid Reveals a Rich Evolutionary Reservoir of Secondary Metabolic Pathways

Phylogenetic analysis indicates that heavy traffic of genetic information between Streptomyces plasmids and chromosomes may facilitate the rapid evolution of secondary metabolite repertoires in these bacteria.

Mycobacterial linear plasmids have an invertron-like structure related to other linear replicons in actinomycetes.

This study has confirmed the presence of such linear plasmids in mycobacteria, including M. avium, and demonstrated that the ends of these replicons are covalently bound with protein(s), suggesting an invertron-like structure.

Streptomyces linear plasmids that contain a phage‐like, centrally located, replication origin

The replication origin of pSLA2 is identified, showing that it contains a series of direct repeats (iterons) within a centrally located gene encoding an essential DNA‐binding protein (Rep1); a second essentialprotein (Rep2), which resembles prokaryotic DNA helicases and has ATPase activity stimulated by single‐stranded DNA, is expressed from the same transcript.

Telomeres of the linear chromosomes of Lyme disease spirochaetes: nucleotide sequence and possible exchange with linear plasmid telomeres

These linear chromosomes have covalently closed hairpin structures at their termini that are similar but not identical to those reported for linear plasmids carried by these organisms, suggesting that there has been historical exchange of genetic information between the linear Plasmids and the right end of the linear chromosome.

The circle is broken: telomere resolution in linear replicons.




Linear plasmids of the bacterium Borrelia burgdorferi have covalently closed ends.

These studies provide direct visual evidence that the linear plasmids have covalently closed ends, which occurs in some animal viruses, but it has not heretofore been described in prokaryotic organisms.

Invertrons, a class of structurally and functionally related genetic elements that includes linear DNA plasmids, transposable elements, and genomes of adeno-type viruses.

A model for replication and integration of invertrons is presented, as well as a model for transposition of transposable elements.

Reconstruction of a Streptomyces linear replicon from separately cloned DNA fragments: existence of a cryptic origin of circular replication within the linear plasmid.

  • D. ShiffmanS. Cohen
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1992
The reconstruction of a functional linear replicon, the 12-kilobase Streptomyces clavuligerus plasmid pSCL, from separate DNA fragments cloned in Escherichia coli on the pUC19 plasmids is reported, indicating the existence of a cryptic origin of circular replication within the linear plasmide.


Results suggest that the linear plasmid-like DNA was isolated from a lysate of Streptomyces sp.

Linear plasmids of Borrelia burgdorferi have a telomeric structure and sequence similar to those of a eukaryotic virus

Findings suggest that the novel linear plasmids of Borrelia originated through a horizontal genetic transfer across kingdoms.

Temperate bacteriophages of Streptococcus pneumoniae that contain protein covalently linked to the 5' ends of their DNA

The protein bound to the DNA in the three phages studied, iodinated in vitro with 125I, has a molecular weight of 23,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and treatment of the complexes with chaotropic agents suggested that the protein is covalently bound toThe 5' termini of the DNA.

The conjugative plasmid SLP2 of Streptomyces lividans is a 50 kb linear molecule

The SLP2 plasmid, demonstrated genetically to exist In Streptomyces lividans by its ability to promote conjugation and to elicit‘pocks’on recipient (SLP2−) cultures, is physically detected and partially homologous to a newly discovered 650 kb linear plasmids in S. parvulus.

Characterization of an autonomously replicating region from the Streptomyces lividans chromosome

The chromosomal replication origin of the plasmidless derivative (TK21) from Streptomyces lividans 66 has been cloned as an autonomously replicating minichromosome (pSOR1) by using the thiostrepton