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Microviridae (taxid:10841)

VIRION

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Non-enveloped, round, T=1 icosahedral symmetry, about 30 nm in diameter. The capsid consists of 12 pentagonal trumpet-shaped pentomers. The virion is composed of 60 copies each of the F, G, and J proteins, and 12 copies of the H protein. There are 12 spikes which are each composed of 5 G and one H proteins.
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GENOME

Circular, ssDNA(+) genome of 4.4 to 6.1kb. replication occurs via dsDNA intermediate and rolling circle.

GENE EXPRESSION

Early and late genes promoters tightly regulate the timing of gene expression, which is crucial for the replication cycle.

ENZYMES

REPLICATION

CYTOPLASMIC

  1. The viral particle attaches to host cell by binding host lipopolysaccharides.
  2. The proteins of the capsid perform Injection of the viral DNA through bacterial membranes into cell cytoplasm.
  3. Host polymerase convert the (+)ssDNA viral genome into a covalently closed dsDNA called replicative form DNA I (RF-I).
  4. Early viral genes are transcribed by host RNA polymerase, producing viral replication proteins.
  5. Viral protein A cleaves RF-I(+) DNA strand at the origin of replication and covalently attaches itself to the DNA.
  6. (+)strand replication occurs by rolling circle, which is converted to dsDNA by host polymerase, generating RF-II molecules (amplification of RF-I).
  7. Late viral genes are transcribed by host RNA polymerase.
  8. Procapsid assembly in the cytoplasm.
  9. Viral protein C binds to replication complex, inducing synthesis and packaging of neo-synthesized (+)ssDNA genomes (RF-III) into procapsids.
  10. Procapsids maturation occurs in host cytoplasm
  11. Mature virions are released from the cell by lysis.
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TAXONOMY Group II: ssDNA viruses
Realm: Monodnaviria
Kingdom: Sangervirae
Phylum: Phixviricota
Class: Malgrandaviricetes
Order: Petitvirales
Family: Microviridae
Subfamily: Bullavirinae
Genus: Alpha3microvirus
G4microvirus
Phix174microvirus
Subfamily: Gokushovirinae
Genus: Chlamydiamicrovirus
Bdellomicrovirus
Spiromicrovirus
ETYMOLOGY Micro from Greek, "small", referring to virion size.
VIRUS
REFERENCE STRAIN Enterobacteria phage alpha3
Sequence | Genome | Proteome
Escherichia virus G4
Sequence | Genome | Proteome
Enterobacteria phage phiX174
Sequence | Genome | Proteome
Chlamydia phage 1
Sequence | Genome | Proteome
Bdellovibrio phage phiMH2K
Sequence | Genome | Proteome
Spiroplasma phage 4
Sequence | Genome | Proteome

Host

NATURAL HOSTS Microvirus: Enterobacteria
Clamydiamicrovirus and Bdellomicrovirus: intracellular parasitic bacteria
Spiromicrovirus: Spiroplasma
INTERACTIONS Cell receptors: PhiX174: LPS

Ecology and disease

GEOGRAPHY Worldwide
TRANSMISSION
ANTIVIRAL DRUGS None

Matching UniProtKB/Swiss-Prot entries

(all links/actions below point to uniprot.org website)

78 entries grouped by strain

11 entries

Bdellovibrio phage phiMH2K (Bacteriophage phiMH2K) reference strain

Select_allDeselect_all
REP_BPPHM Replication-associated protein VP4 (Rep) (VP4) (EC 3.1.21.-) (EC 6.5.1.1)
J_BPPHM DNA binding protein VP8
B_BPPHM Internal scaffolding protein VP3
H_BPPHM Minor spike protein H (H protein) (Pilot protein) (Protein VP2) (VP2)
CAPSD_BPPHM Capsid protein VP1 (VP1)
N_BPPHM Uncharacterized protein N
C_BPPHM Protein VP5
W_BPPHM Uncharacterized protein W
X_BPPHM Uncharacterized protein X
Y_BPPHM Uncharacterized protein Y
Z_BPPHM Uncharacterized protein Z

10 entries

Enterobacteria phage S13 (Bacteriophage S13) reference strain

Select_allDeselect_all
VGA_BPS13 A' protein (GPA)
SCAFB_BPS13 Internal scaffolding protein B (EC 3.4.-.-) (Scaffolding protein B) (GPB)
LYS_BPS13 Lysis protein (E protein) (GPE)
CAPSD_BPS13 Capsid protein F (F protein) (GPF)
G_BPS13 Major spike protein G (G protein) (GPG)
VGH_BPS13 Minor spike protein (H protein) (Pilot protein)
SCAFD_BPS13 External scaffolding protein D (Scaffolding protein D) (GPD)
VGJ_BPS13 Small core protein (J protein)
VGC_BPS13 C protein
VGK_BPS13 K protein

10 entries

Enterobacteria phage phiX174 (Isolate Sanger) (Bacteriophage phi-X174) reference strain

Select_allDeselect_all
REPA_BPPHS Replication-associated protein A (EC 3.1.21.-) (EC 6.5.1.1) (RepA)
LYS_BPPHS Lysis protein E (Protein E) (GPE)

pdb 8G02

SCAFB_BPPHS Internal scaffolding protein B (EC 3.4.-.-) (Scaffolding protein B) (GPB)

pdb 1AL0; 1CD3

CAPSD_BPPHS Capsid protein F (F protein) (GPF)

pdb 1AL0; 1CD3; 1KVP; 2BPA

G_BPPHS Major spike protein G (G protein) (GPG)

pdb 1AL0; 1CD3; 2BPA

H_BPPHS Minor spike protein H (H protein) (Pilot protein)

pdb 4JPN; 4JPP

SCAFD_BPPHS External scaffolding protein D (Scaffolding protein D) (GPD)

pdb 1AL0; 1CD3; 1M0F; 1TX9

J_BPPHS DNA-binding protein J (J protein) (Small core protein)

pdb 1RB8; 2BPA

C_BPPHS Protein C
K_BPPHS Protein K

10 entries

Escherichia phage G4 (Bacteriophage G4) reference strain

Select_allDeselect_all
VGA_BPG4 A protein (GPA)
SCAFB_BPG4 Internal scaffolding protein B (EC 3.4.-.-) (Scaffolding protein B) (GPB)
SCAFD_BPG4 External scaffolding protein D (Scaffolding protein D) (GPD)
VGE_BPG4 Lysis protein (E protein) (GPE)
CAPSD_BPG4 Capsid protein F (F protein) (GPF)

pdb 1GFF

G_BPG4 Major spike protein G (G protein) (GPG)

pdb 1GFF

VGH_BPG4 Minor spike protein (H protein) (Pilot protein)
J_BPG4 DNA-binding protein J (J protein) (Small core protein)

pdb 1GFF

VGC_BPG4 C protein
VGK_BPG4 K protein

10 entries

Escherichia phage alpha3 (Bacteriophage alpha-3) reference strain

Select_allDeselect_all
SCAFB_BPAL3 Internal scaffolding protein B (EC 3.4.-.-) (Scaffolding protein B) (GPB)
VGH_BPAL3 Minor spike protein (H protein) (Pilot protein)
SCAFD_BPAL3 External scaffolding protein D (Scaffolding protein D) (GPD)
CAPSD_BPAL3 Capsid protein F (F protein) (GPF)

pdb 1M06; 1M0F; 1RB8

VGA_BPAL3 A protein (GPA)
VGC_BPAL3 C protein
VGE_BPAL3 Lysis protein (E protein) (GPE)
G_BPAL3 Major spike protein G (G protein) (GPG)

pdb 1M06; 1M0F; 1RB8

J_BPAL3 DNA-binding protein J (J protein) (Small core protein)

pdb 1M06

VGK_BPAL3 K protein

9 entries

Spiroplasma virus 4 (SpV4) reference strain

Select_allDeselect_all
CAPSD_SPV4 Capsid protein VP1 (VP1)

pdb 1KVP; 9CGM

REP_SPV4 Replication-associated protein ORF2 (EC 3.1.21.-) (EC 6.5.1.1) (Rep)
H_SPV4 Minor spike protein H (H protein) (Pilot protein)
J_SPV4 DNA binding protein ORF8

pdb 9CGM

B_SPV4 Internal scaffolding protein ORF3
C_SPV4 Protein ORF5
ORF6_SPV4 Uncharacterized protein ORF6
ORF7_SPV4 Uncharacterized protein ORF7
ORF9_SPV4 Uncharacterized protein ORF9

8 entries

Chlamydia phage 1 (Bacteriophage Chp1) reference strain

Select_allDeselect_all
J_BPCHP DNA binding protein ORF8
REP_BPCHP Replication-associated protein ORF4 (EC 3.1.21.-) (EC 6.5.1.1) (Rep)
CAPSD_BPCHP Capsid protein VP1 (Protein VP1) (VP1)
H_BPCHP Minor spike protein H (H protein) (Pilot protein) (Protein VP2) (VP2)
C_BPCHP Protein ORF5
ORF7_BPCHP Uncharacterized protein ORF7
ORF6_BPCHP Uncharacterized protein ORF6
B_BPCHP Internal scaffolding protein VP3 (Protein VP3) (VP3)

10 entries

Enterobacteria phage phiK (Bacteriophage phi-K)

Select_allDeselect_all
SCAFB_BPPHK Internal scaffolding protein B (EC 3.4.-.-) (Scaffolding protein B) (GPB)
G_BPPHK Major spike protein G (G protein) (GPG)
VGH_BPPHK Minor spike protein (H protein) (Pilot protein)
VGA_BPPHK A protein (GPA)
J_BPPHK DNA-binding protein J (J protein) (Small core protein)
VGC_BPPHK C protein
SCAFD_BPPHK External scaffolding protein D (Scaffolding protein D) (GPD)
VGE_BPPHK Lysis protein (E protein) (GPE)
CAPSD_BPPHK Capsid protein F (F protein) (GPF)
VGK_BPPHK K protein