title: A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria.
abstract: The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria.
authors.affiliation: Instituto de Biomedicina de Valencia (IBV-CSIC), 46010 Valencia, Spain, Centro de Investigación y Tecnología Animal, Instituto Valenciano de Investigaciones Agrarias (CITA-IVIA), Apdo. 187, 12.400 Segorbe, Castellón, Spain, Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, 46113 Moncada, Valencia, Spain, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain, Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra, 31006 Pamplona, Navarra, Spain, Laboratorio de Bacterias Lacticas y Probioticos, Instituto de Agroquimica y Tecnologia de Alimentos-CSIC, 46980 Paterna, Valencia, Spain, Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA, Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298-0678, USA and Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, G12 8TA Glasgow, UK.
authors.forename: Nuria
authors.initials: N
authors.lastname: Quiles-Puchalt
authors.forename: María Ángeles
authors.initials: MÁ
authors.lastname: Tormo-Más
authors.forename: Susana
authors.initials: S
authors.lastname: Campoy
authors.forename: Alejandro
authors.initials: A
authors.lastname: Toledo-Arana
authors.forename: Vicente
authors.initials: V
authors.lastname: Monedero
authors.forename: Iñigo
authors.initials: I
authors.lastname: Lasa
authors.forename: Richard P
authors.initials: RP
authors.lastname: Novick
authors.forename: Gail E
authors.initials: GE
authors.lastname: Christie
authors.forename: José R
authors.initials: JR
authors.lastname: Penadés
mesh_terms: D001483:Base Sequence; D013293:Enterococcus faecalis / Q000821:virology*; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009876:Operon; D011401:Promoter Regions, Genetic; D039002:Prophages / Q000235:genetics / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D017906:Siphoviridae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D019065:Virus Assembly; D057074:Virus Release
chemical_list: D014157:Transcription Factors