Table 2.
Molecular markers/motifs in AIVs previously associated with phenotypic changes.
| Gene | Position a/Residue/Motif (%) b | Phenotype [Reference Number] |
|---|---|---|
| PB2 | 292V (89) | Increased polymerase activity in mammalian cell line and increased virulence in mice [14] |
| 389R (100) | Increased polymerase activity and replication in mammalian cell line [15] | |
| 526R (6) | Increased polymerase activity in mammalian cell line [16] | |
| 598T (100) | Increased polymerase activity and replication in mammalian cells and increased virulence in mice [15] | |
| 627E (100) | Increased virulence in chickens [17] | |
| 715N (89) | Decreased virulence in mice [18] | |
| 89V, 309D (11) | Increased polymerase activity in mammalian cell line and increased virulence in mice [19] | |
| PB1 | 3V (100) | Increased polymerase activity and viral replication in avian and mammalian cell lines [20] |
| 622G (100) | Increased polymerase activity and virulence in mice [21] | |
| 678N (6) | Increased replication in avian and mammalian cell lines [22] | |
| PB1-F2 | 66S (100) | Enhanced replication, virulence and antiviral response in mice [23,24] |
| PA | 37A (100) | Increased polymerase activity in mammalian cell line [25] |
| 63I (89) | Increased polymerase activity and enhanced replication in mammalian cell line, increased virulence in mice [26,27] | |
| 190S (100) | Decreased virulence in mice [28] | |
| 383D (100) | Increased polymerase activity in mammalian and avian cell lines [29,30] | |
| 400P (89) | Decreased virulence in mice [28] | |
| 409S (100) | Increased polymerase activity and replication in mammalian cell line [25] | |
| 497R (6) | Increased polymerase activity in mammalian cell line [31] | |
| HA | 126N (6) | Increased virus binding to α2-6 [32] |
| 214I (6) | Increased virus binding to α2-6 [33] | |
| 326 to 329 (100) | Polybasic cleavage motif sequence required for high pathogenicity avian influenza viruses [34,35,36] | |
| 393E (100) | Increased pH of fusion, decreased HA stability, decreased virulence in mice [37] | |
| NP | 184K (100) | Increased replication in avian cells and virulence in chickens enhanced IFN response [38] |
| NA | 117T (100) | Reduced susceptibility to oseltamivir and zanamivir [39] |
| M1 | 30D (100) | Increased virulence in mice [40] |
| 43M (100) | Increased virulence in mice, chickens, and ducks [41] | |
| 215A (100) | Increased virulence in mice [40] | |
| M2 | 31N (100) | Increased resistance to amantadine and rimantadine [42,43,44,45,46,47,48] |
| NS1 | 42S (100) | Increased virulence and decreased antiviral response in mice [49] |
| 106M (100) | Increased viral replication in mammalian cells and increased virulence in mice [50] | |
| 138F (100) | Increased replication in mammalian cells, decreased interferon response [51] | |
| 149A (100) | Increased virulence and decreased interferon response in chicken [52] | |
| 103F, 106M (100) | Increased virulence in mice [53,54] | |
| 3S, 41K (11) | Enhanced replication in mammalian cells and pathogenicity in mice [55] | |
| 55E, 66E, 138F (100) | Enhanced replication in mammalian cells, decreased IF response [51] | |
| ESEV (227-230, PDZ domain) (100) | Increased virulence in mice Decreased viral replication in mammalian and avian cell lines Increased viral replication and virulence in mice decreased viral replication in human and duck cell lines [56] |
a Codon position. H3 numbering is used for HA; N2 numbering is used for NA; internal genes are numbered according to alignment with A/Goose/Guandong/1/1996 (H5N1). b The percentage of each amino acid in the dataset is shown in parentheses.