Mutations that confer genetic stability to additional genes in influenza viruses

1. A method comprising administering to an avian or a mammal a composition comprising an amount of an isolated recombinant influenza virus having PA, PB1, PB2, NP, NS, M, NA, and HA viral segments, wherein at least one of the viral segments is a PA viral segment encoding PA with a residue at position 443 that is not arginine, a PB1 viral segment encoding PB1 with a residue at position 737 that is not lysine, a PB2 viral segment encoding PB2 with a residue at position 25 that is not valine or a residue at position 712 that is not glutamic acid, a NS viral segment encoding a NS1 with a residue at position 167 that is not proline, a HA viral segment encoding a HA with a residue at position 380 that is not threonine, or any combination thereof, wherein the recombinant influenza virus has enhanced replication relative to a corresponding recombinant influenza virus with a residue at position 443 in PA that is arginine, a residue at position 737 in PB1 that is lysine, a residue at position 25 in PB2 that is valine, a residue at position 712 in PB2 that is glutamic acid, a residue at position 167 in NS1 that is proline, or a residue at position 380 in HA that is threonine, wherein the position 443 in the PA corresponds to position 443 in a PA encoded by SEQ ID NO:1, wherein the position 737 in the PB1 corresponds to position 737 in a PB1 encoded by SEQ ID NO:2, wherein the position 25 or 712 in the PB2 corresponds to position 25 or 712 in a PB2 encoded by SEQ ID NO:3, or wherein the position 167 in the NS1 corresponds to position 167 in a NS1 encoded by SEQ ID NO:6, or wherein the position 380 in the HA corresponds to position 380 in a HA encoded by SEQ ID NO:7.

2. The method of claim 1 wherein the residue at position 443 of PA is K or H, the residue at position 737 of PB1 is H or R, the residue at position 25 of PB2 is A, L, T, I, or G, the residue at position 712 of PB2 is D, the residue at position 167 of NS1 is S, C, M, A, L, I, G or T, or any combination thereof.

3. The method of claim 1 wherein at least one of the viral segments includes a heterologous gene sequence encoding a gene product.

4. The method of claim 3 wherein the heterologous sequence is in the NS viral segment.

5. The method of claim 3 wherein the heterologous sequence is in the M viral segment.

6. The method of claim 3 wherein the heterologous sequence is in the NP viral segment.

7. The method of claim 3 wherein the heterologous sequence is in PA viral segment.

8. The method of claim 3 wherein the heterologous sequence is in PB1 viral segment.

9. The method of claim 3 wherein the heterologous sequence is in the PB2 viral segment.

10. The method of claim 3 wherein the heterologous sequence is 5′ or 3′ to the PA coding sequence in the PA gene segment, 5′ or 3′ to the PB1 coding sequence in the PB1 viral segment.

11. The method of claim 3 wherein the heterologous sequence is 5′ or 3′ to the PB2 coding sequence in the PB2 viral segment.

12. The method of claim 3 wherein the heterologous sequence is 5′ or 3′ to the NS1 coding sequence in the NS viral segment.

13. The method of claim 1 which comprises a further viral segment comprising a heterologous gene sequence encoding a gene product.

14. The method of claim 13 wherein the further viral segment is a NS viral segment, a M viral segment, a NP viral segment, a PA viral segment, a PB1 viral segment or a PB2 viral segment.

15. The method of claim 1 wherein the PB1, PB2, PA, NP, NS, or M viral segment encodes a polypeptide having at least 95% amino acid sequence identity to a corresponding polypeptide encoded by SEQ ID NOs:1-6 or 10-15.

16. The method of claim 1 wherein the composition is administered to a mammal.

17. The method of claim 16 wherein the mammal is a human.