Search results for "tectiviridae"
showing 9 items of 9 documents
Purified Membrane-Containing Procapsids of Bacteriophage PRD1 Package the Viral Genome
2009
Icosahedral-tailed double-stranded DNA (dsDNA) bacteriophages and herpesviruses translocate viral DNA into a preformed procapsid in an ATP-driven reaction by a packaging complex that operates at a portal vertex. A similar packaging system operates in the tailless dsDNA phage PRD1 (Tectiviridae family), except that there is an internal membrane vesicle in the procapsid. The unit-length linear dsDNA genome with covalently linked 5'-terminal proteins enters the procapsid through a unique vertex. Two small integral membrane proteins, P20 and P22, provide a conduit for DNA translocation. The packaging machinery also contains the packaging ATPase P9 and the packaging efficiency factor P6. Here we…
Extending the hosts of Tectiviridae into four additional genera of Gram-positive bacteria and more diverse Bacillus species
2017
Abstract Tectiviridae are composed of tailless bacteriophages with an icosahedral capsid and an inner membrane enclosing a double-stranded 15 kb linear DNA genome. Five of the seven previously studied Tectivirus isolates infect bacteria from Bacillus cereus sensu lato group (Betatectivirus), one distantly related member (PRD1) infect Enterobactericeae (Alpatectivirus) and one recently discovered virus infect Gluconobacter cerinus (Gammatectivirus). Here we expand the host spectrum of Betatectivirus elements to four additional genera (Streptococcus, Exiguobacterium, Clostridium and Brevibacillus) and to more distantly related Bacillus species (B. pumilus and B. flexus) by studying the genome…
Identification of five novel tectiviruses in Bacillus strains: analysis of a highly variable region generating genetic diversity
2013
Our biosphere is abundant with unique and small genes for which no homologs are known. These genes, often referred to as orphans or ORFans, are commonly found in bacteriophage genomes but their origins remain unclear. We discovered five novel tectivirus-like genetic elements by screening more than five-hundred Bacillus strains. A highly variable region (HVR) of these viruses was shown to harbor ORFans in most of these otherwise well-conserved bacteriophages. Previous studies demonstrated that mutations close to this region dramatically alter bacteriophage gene regulation, suggesting that the acquisition of those ORFans may provide a source of genetic diversity that is then subject to geneti…
Identification of a Ligand on the Wip1 Bacteriophage Highly Specific for a Receptor on Bacillus anthracis
2013
ABSTRACT Tectiviridae is a family of tailless bacteriophages with Gram-negative and Gram-positive hosts. The family model PRD1 and its close relatives all infect a broad range of enterobacteria by recognizing a plasmid-encoded conjugal transfer complex as a receptor. In contrast, tectiviruses with Gram-positive hosts are highly specific to only a few hosts within the same bacterial species. The cellular determinants that account for the observed specificity remain unknown. Here we present the genome sequence of Wip1, a tectivirus that infects the pathogen Bacillus anthracis . The Wip1 genome is related to other tectiviruses with Gram-positive hosts, notably, AP50, but displays some interest…
Molecular Characterization of a Variant of Bacillus anthracis-Specific Phage AP50 with Improved Bacteriolytic Activity▿ †
2008
ABSTRACT The genome sequence of a Bacillus anthracis -specific clear plaque mutant phage, AP50c, contains 31 open reading frames spanning 14,398 bp, has two mutations compared to wild-type AP50t, and has a colinear genome architecture highly similar to that of gram-positive Tectiviridae phages. Spontaneous AP50c-resistant B. anthracis mutants exhibit a mucoid colony phenotype.
Icosahedral dsDNA Bacterial Viruses with an Internal Membrane
2008
The icosahedral double-stranded DNA bacteriophages containing an internal membrane belong to two families, the Tectiviridae and the Corticoviridae. Members of the Tectiviridae have a linear dsDNA genome (e.g., PRD1) and those of the Corticoviridae have a circular genome (the only example being PM2). The DNA is covered by a membrane which is in turn covered by a protein capsid. The infection cycle begins when spikes on the capsid recognize the host cell receptor and the virus starts the delivery of the genome into the cell cytoplasm. The replication of the virus genome occurs in the cytoplasm. The members of the Tectiviridae may be virulent or temperate; PM2 is virulent. Virulent bacteriopha…
Probing protein interactions in the membrane-containing virus PRD1.
2015
PRD1 is a Gram-negative bacteria infecting complex tailless icosahedral virus with an inner membrane. This type virus of the family Tectiviridae contains at least 18 structural protein species, of which several are membrane associated. Vertices of the PRD1 virion consist of complexes recognizing the host cell, except for one special vertex through which the genome is packaged. Despite extensive knowledge of the overall structure of the PRD1 virion and several individual proteins at the atomic level, the locations and interactions of various integral membrane proteins and membrane-associated proteins still remain a mystery. Here, we demonstrated that blue native PAGE can be used to probe pro…
Extending the hosts of Tectiviridae into four additional genera of Gram-positive bacteria and more diverse Bacillus species
2018
Tectiviridae are composed of tailless bacteriophages with an icosahedral capsid and an inner membrane enclosing a double-stranded 15 kb linear DNA genome. Five of the seven previously studied Tectivirus isolates infect bacteria from Bacillus cereus sensu lato group (Betatectivirus), one distantly related member (PRD1) infect Enterobactericeae (Alpatectivirus) and one recently discovered virus infect Gluconobacter cerinus (Gammatectivirus). Here we expand the host spectrum of Betatectivirus elements to four additional genera (Streptococcus, Exiguobacterium, Clostridium and Brevibacillus) and to more distantly related Bacillus species (B. pumilus and B. flexus) by studying the genomes of four…
Half a Century of Research on Membrane-Containing Bacteriophages: Bringing New Concepts to Modern Virology
2019
Half a century of research on membrane-containing phages has had a major impact on virology, providing new insights into virus diversity, evolution and ecological importance. The recent revolutionary technical advances in imaging, sequencing and lipid analysis have significantly boosted the depth and volume of knowledge on these viruses. This has resulted in new concepts of virus assembly, understanding of virion stability and dynamics, and the description of novel processes for viral genome packaging and membrane-driven genome delivery to the host. The detailed analyses of such processes have given novel insights into DNA transport across the protein-rich lipid bilayer and the transformati…