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



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.


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.



  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 strain (browse by keywords)

4 entries

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

NCAP_RVFVZ Nucleoprotein (Nucleocapsid protein) (Protein N)
NSS_RVFVZ Non-structural protein S (NSs)
GP_RVFVZ Envelopment polyprotein (M polyprotein) [Cleaved into: NSm-Gn protein (p78 protein); Glycoprotein N ...
L_RVFVZ RNA-directed RNA polymerase L (Protein L) (EC (Large structural protein) (Replicase) ...

4 entries

Uukuniemi virus (strain S23) (Uuk) reference strain

NCAP_UUKS Nucleoprotein (Nucleocapsid protein) (Protein N)
NSS_UUKS Non-structural protein NS-S
L_UUKS RNA-directed RNA polymerase L (Protein L) (EC (Large structural protein) (Replicase) ...
GP_UUKS Envelopment polyprotein (M polyprotein) [Cleaved into: Glycoprotein N (Gn) (Glycoprotein G1); ...

3 entries

Punta toro phlebovirus

NSS_PTPV Non-structural protein NS-S
NCAP_PTPV Nucleoprotein (Nucleocapsid protein) (Protein N)
GP_PTPV Envelopment polyprotein (M polyprotein) [Cleaved into: Non-structural protein NSm; Glycoprotein N ...

3 entries

Toscana virus (Tos)

NSS_TOSV Non-structural protein NS-S
NCAP_TOSV Nucleoprotein (Nucleocapsid protein) (Protein N)
L_TOSV RNA-directed RNA polymerase L (Protein L) (EC (Large structural protein) (Replicase) ...

2 entries

Sandfly fever sicilian virus (SFS)

NCAP_SFSV Nucleoprotein (Nucleocapsid protein) (Protein N)
NSS_SFSV Non-structural protein NS-S

1 entry

Rift valley fever virus (RVFV)

GP_RVFV Envelopment polyprotein (M polyprotein) [Cleaved into: NSm-Gn protein; Glycoprotein N (Gn) ...