Construction of a microphage variant of filamentous bacteriophage

J Mol Biol. 1992 Dec 5;228(3):720-4. doi: 10.1016/0022-2836(92)90858-h.


The intergenic region in the genome of the Ff class of filamentous phage (comprising strains fl, fd and M13) genome constitutes 8% of the viral genome, and has essential functions in DNA replication and phage morphogenesis. The functional domains of this region may be inserted into separate sites of a plasmid to function independently. Here, we demonstrate the construction of a plasmid containing, sequentially, the origin of (+)-strand synthesis, the packaging signal and a terminator of (+)-strand synthesis. When host cells harboring this plasmid (pLS7) are infected with helper phage they produce a microphage particle containing all the structural elements of the mature, native phage. The microphage is 65 A in diameter and about 500 A long. It contains a 221-base single-stranded circle of DNA coated by about 95 copies of the major coat protein (gene 8 protein).

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacteriophage M13 / genetics*
  • Bacteriophage M13 / ultrastructure
  • Base Sequence
  • Coliphages / genetics*
  • Coliphages / ultrastructure
  • DNA Replication
  • DNA, Recombinant
  • DNA, Viral / genetics*
  • Gene Expression Regulation, Viral
  • Helper Viruses / genetics
  • Molecular Sequence Data
  • Morphogenesis
  • Nucleic Acid Conformation
  • Particle Size
  • Plasmids / genetics*
  • Plasmids / ultrastructure


  • DNA, Recombinant
  • DNA, Viral