title: KSY1, a lactococcal phage with a T7-like transcription.
abstract: The virulent lactococcal phage KSY1 possesses a large elongated capsid (223 nm long, 45 nm wide) and a short tail (32 nm). This phage of the Podoviridae group (C3 morphotype) has a linear 79,232-bp double-stranded DNA genome, which encodes 131 putative proteins and 3 tRNAs. This is the first description of the genome of a phage of this morphotype. KSY1 possesses a T7-like transcription system, including an RNA polymerase and a series of specific promoters, showing sequence homology to other known T7-like RNA polymerase promoters. Late stages of KSY1 multiplication are resistant to rifampicin. Otherwise, KSY1 shares limited similarity with other Podoviridae phages. Fourteen KSY1 structural proteins were identified by SDS-PAGE analysis. Among these proteins, those forming the distal tail structure and likely involved in host recognition are encoded by a 5-kb genomic region of KSY1. This region consists of a mosaic of DNA segments highly homologous to DNA of other lactococcal phages, suggesting an horizontal gene transfer.
authors.affiliation: Laboratoire de Génétique Microbienne, INRA, 78352 Jouy-en-Josas, France. Alain.Chopin@jouy.inra.fr
authors.forename: Alain
authors.initials: A
authors.lastname: Chopin
authors.forename: Hélène
authors.initials: H
authors.lastname: Deveau
authors.forename: S Dusko
authors.initials: SD
authors.lastname: Ehrlich
authors.forename: Sylvain
authors.initials: S
authors.lastname: Moineau
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Chopin
mesh_terms: D017123:Bacteriophage T7 / Q000235:genetics; D016679:Genome, Viral; D017045:Lactococcus / Q000821:virology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D017902:Podoviridae / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry
chemical_list: D014764:Viral Proteins