Microvirus of Chlamydia psittaci strain Guinea pig inclusion conjunctivitis: Isolation and molecular characterization

Ru Ching Hsia, Li Min Ting, Patrik M. Bavoil

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The authors report the isolation and molecular characterization of a bacteriophage, CPG1, which infects Chlamydia psittaci strain Guinea pig inclusion Conjunctivitis. Purified virion preparations contained isometric particles of 25 nm diameter, superficially similar to spike-less members of the X174 family of bacteriophages. The single-stranded circular DNA genome of CPG1 included five large ORFs, which were similar to ORFs in the genome of a previously described Chlamydia bacteriophage (Chp1) that infects avian C. psittaci. Three of the ORFs encoded polypeptides that were similar to those in a phage infecting the mollicute Spiroplasma melliferum, a pathogen of honeybees. Lesser sequence similarities were seen between two ORF products and the major capsid protein of the X174 coliphage family and proteins mediating rolling circle replication initiation in phages, phagemids and plasmids. Phage CPG1 is the second member of the genus Chlamydiamicrovirus, the first to infect a member of a Chlamydia species infecting mammals. Similarity searches of the nucleotide sequence further revealed a highly conserved (75% identity) 375 base sequence integrated into the genome of the human pathogen Chlamydia pneumoniae. This genomic segment encodes a truncated 113 residue polypeptide, the sequence of which is 72% identical to the amino-terminal end of the putative replication initiation protein of CPG1. This finding suggests that C. pneumoniae has been infected by a phage related to CPG1 and that infection resulted in integration of some of the phage genome into the C. pneumoniae genome.

Original languageEnglish (US)
Pages (from-to)1651-1660
Number of pages10
JournalMicrobiology
Volume146
Issue number7
DOIs
Publication statusPublished - Jul 2000

    Fingerprint

Keywords

  • Bacteriophage
  • Capsid protein
  • Chlamydia
  • Rep protein

ASJC Scopus subject areas

  • Microbiology

Cite this