イノウイルス

関: filamentous bacteriophage

WordNet

any of a group of picornaviruses that are responsible for many upper respiratory infections

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/19 07:01:59」(JST)

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Inovirus is a genus of viruses, in the family Inoviridae. Bacteria and gram-negative bacteria (specifically Enterobacteriaceae, Pseudomonadaceae, Spirillaceae, Xanthomonadaceae, Clostridium and Propionibacterium) serve as natural hosts. There are currently 36 species in this genus including the type species Enterobacteria phage M13.^[1]^[2] The name of the genus is derived from the Greek word 'nos' meaning 'muscle'.

Taxonomy

Group: ssDNA

Order: Unassigned

Family: Inoviridae
- Genus: Inovirus
  Enterobacteria phage AE2
  
  Enterobacteria phage C-2
  
  Enterobacteria phage dA
  
  Enterobacteria phage Ec9
  
  Enterobacteria phage f1
  
  Enterobacteria phage fd
  
  Enterobacteria phage HR
  
  Enterobacteria phage I2-2
  
  Enterobacteria phage If1
  
  Enterobacteria phage IKe
  
  Enterobacteria phage M13
  
  Enterobacteria phage PR64FS
  
  Enterobacteria phage SF
  
  Enterobacteria phage tf-1
  
  Enterobacteria phage X
  
  Enterobacteria phage X-2
  
  Enterobacteria phage ZJ/2
  
  Pseudomonas phage Pf1
  
  Pseudomonas phage Pf2
  
  Pseudomonas phage Pf3
  
  Vibrio phage 493
  
  Vibrio phage CTX
  
  Vibrio phage fs1
  
  Vibrio phage fs2
  
  Vibrio phage v6
  
  Vibrio phage Vf12
  
  Vibrio phage Vf33
  
  Vibrio phage VSK
  
  Xanthomonas phage Cf16
  
  Xanthomonas phage Cf1c
  
  Xanthomonas phage Cf1t
  
  Xanthomonas phage Cf1tv
  
  Xanthomonas phage Lf
  
  Xanthomonas phage Xf
  
  Xanthomonas phage Xfo
  
  Xanthomonas phage Xfv

^[2]

Virology

The virions consist of a non enveloped, filamentous capsid with helical symmetry.^[3] The virions are between 760 and 1950 nanometers (nm) in length and 6-8 nm in width.

There are five or more proteins in the capsid: gp8 (the major capsid protein); gp6, gp7 and gp8 (minor capsid proteins); and gp3 which acts as the initial host binding protein.

The genomes are non segmented, circular, positive-sense, single-stranded DNA 4.4-8.5 kilobases in length. They encode 4 to 11 proteins.

Replication of the genome occurs via a dsDNA intermediate and the rolling circle mechanism.

Gene transcription is by the host's cellular machinery each gene having a specific promoter.

Protein gp2 is an essential gene because of its role in viral DNA replication. It binds to the origin of replication (ori), cleaves the dsDNA replicative form I and becomes covalently bound to it via phosphotyrosine bond, generating the dsDNA replicative form II. Viral DNA replication initiates at the 3'-OH of the cleavage site. After one round of rolling circle synthesis, gp2 is linked to the newly synthesized ssDNA and joins the ends of the displaced strand to generate a circular single-stranded molecule ready to be packed into a virion.

The major coat protein gp8 has a parallel coiled-coil structure.

Genus	Structure	Symmetry	Capsid	Genomic Arrangement	Genomic Segmentation
Inovirus	Rod-shaped	Helical	Non-Enveloped	Circular	Monopartite

Life cycle

There are six steps in the life cycle

1. Adsorption to the host via specific receptor(s)

2. Movement of the viral DNA into the host cell

3. Conversion of the single strand form to a double stranded intermediate

4. Replication of the viral genome

5. Synthesis of the new virions

6. Release of the new virons from the host

A typical replication cycle normally take 10–15 minutes to complete.

Genus	Host Details	Tissue Tropism	Entry Details	Release Details	Replication Site	Assembly Site	Transmission
Inovirus	Gram-negative bacteria	None	Pilus adsorption	Secretion	Cytoplasm	Cytoplasm	Pilus

Adsorption

This is mediated by one of the viral proteins (gp3) binding to the host receptor

Entry into the host cell

Conversion to double stranded form

The conversion from single stranded to double stranded form is carried out by the host's own DNA polymerase. The host's RNA polymerase binds to the viral genome and syntheses RNA. Some of this RNA is translated and the remainder is used to initiate DNA replication.

Replication

This is initiated when a viral endonuclease (gp2) nicks the double stranded intermediate. This nicking site is specific and the sequence around the site highly symmetrical. The activity of gp2 is regulated by two other viral proteins: gp5 (single strand binding protein) and gp10. New viral genomes are produced via the rolling circle mechanism. These new single strand DNA sequences become templates for further DNA and RNA synthesis. When sufficient gp5 has accumulated within the cell, further DNA synthesis is halted and virion assembly begins.

Virion assembly

This is a complex process. It is initiated by the formation of a complex of gp1, gp7, gp9 and gp11 along with the single stranded DNA and gp%. It begins at a specific sequence within the DNA which is predicted to have a hairpin formation. Assembly continues at the membrane where ~1500 subunits of gp5 are displaced by ~2700 subunits of gp8 (the number of major capsid protein subunits per virion). This process involves both gp1 and gp11. Assembly is completed by the addition of the viral proteins gp3 and gp6. In hosts with both an inner and outer membrane adhesion zones are created by gp4, a process that may also involve gp1.

Virion release

This may involve host lysis but alternatively productive infection may occur by budding from the host membrane. This pattern is typically seen in the Plectivirus genus.

The phage DNA may integrate into the host genome via site-specific homologous recombination.

Notes

A number of exceptions to this life cycle are known. Lysogenic species, which encode integrases, exist within this family.

The phage DNA may integrate into the host genome via site-specific homologous recombination. Most phages that do integrate into the host genome encode a recombinase. Inoviruses do not encode this enzyme. The phages that infect hosts in the genus Vibro highjack the chromosome dimer resolution system of their hosts in order to integrate into the genome of the host.

Relevance

At least one of the viruses (Vibrio phage CTX) is medically important as it encodes the cholera toxin.^[4]

The type species is Enterobacteria phage M13. This phage has been extensively used in experimental work in microbiology.

Non biological uses

The phage M13 has been used to make nanosized (10−20 µm in diameter) fibers.^[5]

References

^ "Viral Zone". ExPASy. Retrieved 15 June 2015.
^ ^a ^b ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
^ Welsh LC, Marvin DA, Perham RN (1998) Analysis of X-ray diffraction from fibres of Pf1 Inovirus (filamentous bacteriophage) shows that the DNA in the virion is not highly ordered. J Mol Biol 284(5):1265-1271
^ Bhattacharya T, Chatterjee S, Maiti D, Bhadra RK, Takeda Y, Nair GB, Nandy RK (2006) Molecular analysis of the rstR and orfU genes of the CTX prophages integrated in the small chromosomes of environmental Vibrio cholerae non-O1, non-O139 strains. Environ Microbiol 8(3):526-634
^ Lee S-W, Belcher AM (2004) Virus-Based Fabrication of micro- and nanofibers Using electrospinning. Nano Letters 4 (3) 387–390 doi:10.1021/nl034911t

External links

Viralzone: Inovirus
ICTV
Viral sequences [1]
ViralZone: Inoviridae (Familia)

English Journal

Tautomerism provides a molecular explanation for the mutagenic properties of the anti-HIV nucleoside 5-aza-5,6-dihydro-2'-deoxycytidine.

Li D1, Fedeles BI1, Singh V1, Peng CS2, Silvestre KJ2, Simi AK3, Simpson JH2, Tokmakoff A4, Essigmann JM5.
Proceedings of the National Academy of Sciences of the United States of America.Proc Natl Acad Sci U S A.2014 Aug 12;111(32):E3252-9. doi: 10.1073/pnas.1405635111. Epub 2014 Jul 28.
Viral lethal mutagenesis is a strategy whereby the innate immune system or mutagenic pool nucleotides increase the error rate of viral replication above the error catastrophe limit. Lethal mutagenesis has been proposed as a mechanism for several antiviral compounds, including the drug candidate 5-az
PMID 25071207

Interaction of Kaposi's sarcoma-associated herpesvirus ORF6 protein with single-stranded DNA.

Ozgur S1, Griffith J2.
Journal of virology.J Virol.2014 Aug;88(15):8687-95. doi: 10.1128/JVI.03652-13. Epub 2014 May 21.
Kaposi's sarcoma-associated herpesvirus (KSHV) ORF6 is homologous to the herpes simplex virus 1 (HSV-1) ICP8 and Epstein-Barr virus (EBV) BALF2 proteins. Here, we describe its single-stranded DNA (ssDNA) binding properties. Based on previous findings with ICP8 and BALF2, a 60-amino-acid C-terminal d
PMID 24850743

Insights into the diversity of φRSM phages infecting strains of the phytopathogen Ralstonia solanacearum complex: regulation and evolution.

Askora A1, Kawasaki T, Fujie M, Yamada T.
Molecular genetics and genomics : MGG.Mol Genet Genomics.2014 Aug;289(4):589-98. doi: 10.1007/s00438-014-0835-3. Epub 2014 Mar 12.
The filamentous φRSM phages (φRSM1 and φRSM3) have integration/excision capabilities in the phytopathogenic bacterium Ralstonia solanacearum. In the present study, we further investigated φRSM-like sequences present in the genomes of R. solanacearum strains belonging to the four major evolutiona
PMID 24619102