title: Microvirus of chlamydia psittaci strain guinea pig inclusion conjunctivitis: isolation and molecular characterization.
abstract: The authors report the isolation and molecular characterization of a bacteriophage, &phi;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 &phi;X174 family of bacteriophages. The single-stranded circular DNA genome of &phi;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 &phi;X174 coliphage family and proteins mediating rolling circle replication initiation in phages, phagemids and plasmids. Phage &phi;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 &phi;CPG1. This finding suggests that C. pneumoniae has been infected by a phage related to &phi;CPG1 and that infection resulted in integration of some of the phage genome into the C. pneumoniae genome.
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK1.
authors.forename: Ru-Ching
authors.initials: RC
authors.lastname: Hsia
authors.affiliation: Department of Medicine, University of California at San Francisco, Box 0868, San Francisco,CA 94143-0868, USA2.
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Ting
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK1.
authors.forename: Patrik M
authors.initials: PM
authors.lastname: Bavoil
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000737:chemistry / Q000235:genetics; D016993:Chlamydophila pneumoniae / Q000821:virology; D002691:Chlamydophila psittaci / Q000821:virology*; D003235:Conjunctivitis, Inclusion / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D016679:Genome, Viral; D006168:Guinea Pigs; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D017915:Microvirus / Q000737:chemistry / Q000235:genetics* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames; D016415:Sequence Alignment; D016662:Virus Integration
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral