N4-like viruses
Encyclopedia
The N4-like viruses are bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...

s within the Podoviridae
Podoviridae
The Podoviridae are a family of bacteriophages. Unlike the other families of tailed viruses this family has short tails that are non contractile.There are at least 74 species in this family.-Virology:...

family.

Bacteriophage N4 is type species for this genus and was originally isolated from sewers in Genoa
Genoa
Genoa |Ligurian]] Zena ; Latin and, archaically, English Genua) is a city and an important seaport in northern Italy, the capital of the Province of Genoa and of the region of Liguria....

, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 and is active against Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

K-12. Recently, a number of genomically related phages were isolated, infecting Silicibacter
Silicibacter
In taxonomy, Silicibacter is a genus of the Rhodobacteraceae.-External links:...

and Sulfitobacter
Sulfitobacter
In taxonomy, Sulfitobacter is a genus of the Rhodobacteraceae.-External links:...

(DSS3ɸ2 and EE36ɸ1) as well as a number of Pseudomonas
Pseudomonas
Pseudomonas is a genus of gammaproteobacteria, belonging to the family Pseudomonadaceae containing 191 validly described species.Recently, 16S rRNA sequence analysis has redefined the taxonomy of many bacterial species. As a result, the genus Pseudomonas includes strains formerly classified in the...

phages (LUZ7, LIT1 and PEV2)

Virology

The virus's virion have icosahedral
Icosahedron
In geometry, an icosahedron is a regular polyhedron with 20 identical equilateral triangular faces, 30 edges and 12 vertices. It is one of the five Platonic solids....

 heads ~70 nm
Nanometre
A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...

 and short tails 10 nm, and contain short fibers originating from the junction between the head and tail. All the phages of this genus are strictly virulent and contain a linear dsDNA genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 (with terminal repeats) in the range of 70-75kb.

Molecular biology

A remarkable feature of this clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of phages is the use of three distinct RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 polymerase
Polymerase
A polymerase is an enzyme whose central function is associated with polymers of nucleic acids such as RNA and DNA.The primary function of a polymerase is the polymerization of new DNA or RNA against an existing DNA or RNA template in the processes of replication and transcription...

s during its infection cycle. A giant virion-encapsulated RNAP polymerase which is co-injected (early transcription), a heterodimeric
Protein dimer
In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...

phage RNA polymerase (middle region) and the host RNA polymerase (recognizes late promoters).
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