Betainfluenzavirus (taxid:197912)
VIRION
Enveloped. Usually rounded but can be filamentous. The virions are 80-120 nm in diameter.
GENOME
segmented ssRNA(-) linear genome, encapsidated by nucleoprotein (NP) Contains 8 segments coding for 11 proteins. Segments size range from 890 to 2,341nt. Genome total size is 13.5Kb
GENE EXPRESSION
Viral RNA polymerase (PB1, PB2 and PA) transcribes one mRNA from each genome segment. Transcription is primed by cap snatching. mRNA are polyadenylated by the viral polymerase stuttering on a poly U track. M and NS mRNA can be alternatively spliced, giving rise to mRNA coding for BM" and NEP proteins. NB is translated by leaky scanning from the NA mRNA.
ENZYMES
- RNA-dependent RNA polymerase [PB1]
- Cap Snatching endonuclease [PA]
- Neuraminidase [NA]
REPLICATION
NUCLEUS
- Virus attaches to sialic acid receptor though HA protein and is endocytosed by clathrins in the host cell.
- endosome acidification induces fusion of virus membrane with the vesicle membrane; encapsidated RNA segments migrate to the nucleus.
- Transcription of genomic segments by the viral polymerase produces mRNAs that are capped and polyadenylated by the viral polymerase.
- Replication of genomic segments.
- High level of M1 protein induces genomes segments export from nucleus by NEP protein.
- Virus assembly and budding occurs at the plasma membrane.
Host-virus interaction
Innate immune response inhibition
Influenza B virus inhibits the cascade leading to production of interferon-beta by targeting different cellular proteins. NS1 inhibits host ISG15 activation as well as PKR.
Matching UniProtKB/Swiss-Prot entries
(all links/actions below point to uniprot.org website)78 entries grouped by protein
6 entries
Matrix protein 2 (BM2)
6 entries
Hemagglutinin
6 entries
Matrix protein 1 (M1)
6 entries
Nucleoprotein (Nucleocapsid protein) (Protein N)
2 entries
Nuclear export protein (NEP) (Non-structural protein 2) (NS2)
12 entries
Neuraminidase (EC 3.2.1.18)
16 entries
Non-structural protein 1 (NS1) (NS1A)
5 entries
Polymerase acidic protein (EC 3.1.-.-) (RNA-directed RNA polymerase subunit P2)
4 entries
Polymerase basic protein 2 (RNA-directed RNA polymerase subunit P3)
4 entries
RNA-directed RNA polymerase catalytic subunit (EC 2.7.7.48) (Polymerase basic protein 1) (PB1) (RNA-directed RNA polymerase subunit P1)
11 entries