TABLE 1.
5′ and 3′ UTR, structural proteins, and nonstructural proteins of members of the Flaviviridae and their function
| Protein | Hepacivirus | Flavivirus | Pestivirus |
|---|---|---|---|
| 5′ UTR | 342 bases (80) | 67–132 bases (33) | 385 bases (37) |
| Structural proteins | |||
| CAP | —a | Type I m7GpppN1mpN2 (245) | — |
| IRES | HCV (135, 232) | — | BVDV (188), CSFV (196, 207) |
| Npro | — | — | Autoprotease (p20) (248) |
| C | Nucleocapsid protein (12) | Nucleocapsid protein (33) | Nucleocapsid protein (p14) |
| Pre-M | — | Precursor membrane glycoprotein (244) | — |
| E | — | Envelope glycoprotein (33) | — |
| Erns | — | — | Envelope glycoprotein with RNase activity (gp48) (25) |
| E1 | Envelope glycoprotein (12) | — | Envelope glycoprotein (gp25) (200) |
| E2 | Envelope glycoprotein (12) | — | Envelope glycoprotein (gp53) (200) |
| Nonstructural proteins | |||
| NS1 | — | Role in early RNA replication (144), secreted after glycosylation (33) | — |
| NS2 | Constituent of the protease (12) | — | Function unknown (p54) (17) |
| NS2A | — | Function unknown; binds strongly to the 3′UTR, NS3, and NS5 (152) | — |
| NS2B | — | Cofactor of the NS3 (33, 152) | — |
| NS3 | Constituent of the protease; N terminus: serine-type protease; C terminus: NTPase-helicase (12) | Serine protease; NTPase-helicase (33) | N terminus: serine-type protease, C terminus: NTPase-helicase (p80) (252) |
| Expression characteristic for cytopathic biotypes (223) | |||
| NS2-3 | — | — | Expression characteristic for noncytopathic biotypes (223) |
| NS4A | NS3 protease factor (12) | Function unknown; binds strongly to most of the other nonstructural proteins (152) | NS3 protease cofactor (p10) (252) |
| NS4B | Function unknown | Function unknown | Function unknown (p30) (236) |
| NS5 | — | RdRp (33) | — |
| NS5A | Induction of interferon resistance by repression of the cellular PKR protein kinase (68) | — | Function unknown (p58) |
| NS5B | RdRp (12) | — | RdRp (p75) |
| 3′UTR | Variable length (120) | 114–585 bases (33) | 225 bases (37) |
a
—, does not apply to this genus.