Identification and nucleotide sequence analysis of an open reading frame involved in high-frequency conversion of turbid to clear plaque mutants of filamentous phage Cf1t

Virology. 1991 Nov;185(1):316-22. doi: 10.1016/0042-6822(91)90779-b.

Abstract

Clear plaque mutants (Cf1c) isolated from the temperate filamentous phage Cf1t occurred at a frequency of approximately 10(-3). The pahge yield from Cf1c-infected cells was higher than that from Cf1t-infected cells. Results of spot complementation tests implied that the turbid plaque phenotype is dominant. DNA fragment substitution studies indicated that a NcoI/KpnI fragment of 591 bp was responsible for the determination of plaque turbidity. Sequence data from four Cf1c isolates revealed base pair alterations and a deletion located in the upstream region of an open reading frame (ORFII) which might encode a 18.2-kDa protein. When the ORFII in Cf1t was disrupted by a frameshift mutation, this recombinant phage formed clear plaques. These observations suggest that ORFII may participate in the formation of turbid plaques. ORFII does not show significant homology with the sequence of f1 gpII, gpV, or other known phage proteins.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacteriophages / genetics*
  • Bacteriophages / physiology
  • Base Sequence
  • DNA, Recombinant / metabolism
  • DNA, Viral / genetics
  • Frameshift Mutation*
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Open Reading Frames*
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Viral Plaque Assay
  • Virus Replication
  • Xanthomonas campestris / genetics*
  • Xanthomonas campestris / physiology

Substances

  • DNA, Recombinant
  • DNA, Viral