title: Lactococcal abortive infection protein AbiV interacts directly with the phage protein SaV and prevents translation of phage proteins.
abstract: AbiV is an abortive infection protein that inhibits the lytic cycle of several virulent phages infecting Lactococcus lactis, while a mutation in the phage gene sav confers insensitivity to AbiV. In this study, we have further characterized the effects of the bacterial AbiV and its interaction with the phage p2 protein SaV. First, we showed that during phage infection of lactococcal AbiV(+) cells, AbiV rapidly inhibited protein synthesis. Among early phage transcripts, sav gene transcription was slightly inhibited while the SaV protein could not be detected. Analyses of other phage p2 mRNAs and proteins suggested that AbiV blocks the activation of late gene transcription, probably by a general inhibition of translation. Using size exclusion chromatography coupled with on-line static light scattering and refractometry, as well as fluorescence quenching experiments, we also demonstrated that both AbiV and SaV formed homodimers and that they strongly and specifically interact with each other to form a stable protein complex.
authors.affiliation: Center for Systems Microbiology, Department of Systems Biology, Matematiktorvet, Bldg. 301, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Haaber
authors.forename: Julie E
authors.initials: JE
authors.lastname: Samson
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Labrie
authors.forename: Valérie
authors.initials: V
authors.lastname: Campanacci
authors.forename: Christian
authors.initials: C
authors.lastname: Cambillau
authors.forename: Sylvain
authors.initials: S
authors.lastname: Moineau
authors.forename: Karin
authors.initials: K
authors.lastname: Hammer
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001435:Bacteriophages / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D015153:Blotting, Western; D005814:Genes, Viral / Q000235:genetics; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D014176:Protein Biosynthesis / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D012333:RNA, Messenger; D054334:Viral Regulatory and Accessory Proteins