Phlebovirus

VIRION

Enveloped, spherical. Diameter from 80 to 120nm. Glycoproteins at the surface of the envelope are arranged on an icosahedral lattice, with T=12 symmetry.

GENOME

Segmented Negative-stranded RNA linear genome, L segment is about 6.4kb, M segment about 3.2kb and S segment about 1.7kb.
Encodes for six proteins.

GENE EXPRESSION

Transcription starts by viral RNA dependent RNA polymerase (L) binding to a promoter on each encapsidated segment, and is terminated by a strong hairpin sequence at the end of each gene. These are capped by L protein during synthesis using cap snatching , but are not polyadenylated.
S segment uses ambisense strategy to encode for several proteins: both genomic and antigenomic RNA are transcribed. The hairpin sequence is a stop polymerase signal which prevents ambisense transcription from producing dsRNA. M segment encodes for several polyproteins by leaky scanning, which are cleaved by host protease into Nsm-GN, Nsm, NSm',Gn and Gc proteins.

REPLICATION

CYTOPLASMIC

  1. Virus attaches to host receptors though Gn-Gc glycoprotein dimer, and is endocytosed into vesicles in the host cell.
  2. Fusion of virus membrane with the vesicle membrane; ribonucleocapsid segments are released in the cytoplasm.
  3. Transcription, viral mRNAs are capped in the cytoplasm.
  4. Replication presumably starts when enough nucleoprotein is present to encapsidate neo-synthetized antigenomes and genomes.
  5. The ribonucleocapsids buds at Golgi apparatus, releasing the virion by exocytosis.

Host-virus interaction

Inhibition of host transcription initiation

The Rift valley fever virus NSs protein instead plays a role in the inhibition of the host transcription initiation by acting on host TFIIH.

Matching UniProtKB/Swiss-Prot entries

17 entries grouped by protein (browse by keywords)

All proteins are shown (view only 11 complete proteome entries)

4 entries

Envelopment polyprotein (M polyprotein)

Select_allDeselect_all
GP_RVFVZ
Rift valley fever virus (strain ZH-548 M12) (RVFV) reference strain
GP_UUKS
Uukuniemi virus (strain S23) (Uuk) reference strain
GP_PTPV
Punta toro phlebovirus
GP_RVFV
Rift valley fever virus (RVFV)

3 entries

RNA-directed RNA polymerase L (Protein L) (EC 2.7.7.48) (Large structural protein) (Replicase) (Transcriptase)

Select_allDeselect_all
L_RVFVZ
Rift valley fever virus (strain ZH-548 M12) (RVFV) reference strain
L_UUKS
Uukuniemi virus (strain S23) (Uuk) reference strain
L_TOSV
Toscana virus (Tos)

5 entries

Nucleoprotein (Nucleocapsid protein) (Protein N)

Select_allDeselect_all
NCAP_RVFVZ
Rift valley fever virus (strain ZH-548 M12) (RVFV) reference strain
NCAP_UUKS
Uukuniemi virus (strain S23) (Uuk) reference strain
NCAP_PTPV
Punta toro phlebovirus
NCAP_SFSV
Sandfly fever sicilian virus (SFS)
NCAP_TOSV
Toscana virus (Tos)

5 entries

Non-structural protein NS-S

Select_allDeselect_all
NSS_RVFVZ
Rift valley fever virus (strain ZH-548 M12) (RVFV) reference strain

Non-structural protein S (NSs)

NSS_UUKS
Uukuniemi virus (strain S23) (Uuk) reference strain
NSS_PTPV
Punta toro phlebovirus
NSS_SFSV
Sandfly fever sicilian virus (SFS)
NSS_TOSV
Toscana virus (Tos)