Orthomyxoviridae (taxid:11308)
VIRION

Molecular biology
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. MP and NS mRNA can be alternatively spliced, giving rise to mRNA coding for M2 and NEP proteins. PB1-F2 is translated by leaky scanning from the PB1 mRNA.
ENZYMES
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 ESCRT-independent budding occurs at the plasma membrane.
Influenza species tropism
It is generally accepted that human influenza viruses preferentially bind to host glycoproteins/glycolipids containing sialic acids in alpha 2,6 linkage, whereas avian influenza viruses bind to those containing sialic acids in alpha 2,3 linkage.
Recent studies have shown that the Human traches and alvoeli epithelial cells are mainly expressing alpha 2,6 sialic acids, when only alveoli are expressing alpha 2,3 sialic acids PubMed. This could explain why avian viruses could succesfully infect humans only when breathed at high doses. Indeed the trachea and bronchioles are much easier to reach than the alveoli for aerial-transmitted virus.
These results are debated, and investigations are needed to understand the whole picture PubMed
Infectious salmon anemia virus (isolate Atlantic salmon/Norway/810/9/99) taxid:652965
Protein | ModelArchive |
Polymerase basic protein 2 (PB2) (Protein 3) (P3) (RNA-directed RNA polymerase subunit... | ma-jd-viral-36301 |
Influenza A virus (A/Hong Kong/1073/99(H9N2)) taxid:130760
Influenza A virus (strain A/Goose/Guangdong/1/1996 H5N1 genotype Gs/Gd) taxid:93838
Influenza C virus (strain C/Ann Arbor/1/1950) taxid:11553
Thogoto virus (isolate SiAr 126) taxid:126796
Protein | ModelArchive |
Nucleoprotein (Nucleocapsid protein) (Protein N) | ma-jd-viral-32091 |
Thogotovirus thogotoense taxid:11569
Protein | ModelArchive |
Nucleoprotein | ma-jd-viral-32091 |
Wellfleet Bay virus taxid:1566309
Matching UniProtKB/Swiss-Prot entries
(all links/actions below point to uniprot.org website)1435 entries grouped by protein
6 entries
Matrix protein 2 (BM2)
3 entries
Envelope glycoprotein
1 entry
Fusion glycoprotein F0 (Protein 3) (P3)
135 entries
Hemagglutinin
123 entries
Matrix protein 1 (M1)
112 entries
Matrix protein 2 (Proton channel protein M2)
5 entries
Polyprotein p42
1 entry
Protein ML (ML)
172 entries
Nucleoprotein (Nucleocapsid protein) (Protein N)
121 entries
Nuclear export protein (NEP) (Non-structural protein 2) (NS2)
136 entries
Neuraminidase (EC 3.2.1.18)
140 entries
Non-structural protein 1 (NS1) (NS1A)
1 entry
Protein P7 (P7)
101 entries
Polymerase acidic protein (EC 3.1.-.-) (RNA-directed RNA polymerase subunit P2)
90 entries
Protein PA-X
69 entries
Protein PB1-F2
100 entries
Polymerase basic protein 2 (RNA-directed RNA polymerase subunit P3)
5 entries
PB2-S1
103 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
Glycoprotein NB
Infectious salmon anemia virus (isolate Atlantic salmon/Norway/810/9/99) taxid:652965
Protein | ModelArchive |
Polymerase basic protein 2 (PB2) (Protein 3) (P3) (RNA-directed RNA polymerase subunit... | ma-jd-viral-36301 |
Influenza A virus (A/Hong Kong/1073/99(H9N2)) taxid:130760
Influenza A virus (strain A/Goose/Guangdong/1/1996 H5N1 genotype Gs/Gd) taxid:93838
Influenza C virus (strain C/Ann Arbor/1/1950) taxid:11553
Thogoto virus (isolate SiAr 126) taxid:126796
Protein | ModelArchive |
Nucleoprotein (Nucleocapsid protein) (Protein N) | ma-jd-viral-32091 |
Thogotovirus thogotoense taxid:11569
Protein | ModelArchive |
Nucleoprotein | ma-jd-viral-32091 |