Methods and compositions for expressing negative-sense viral RNA in canine cells
The present invention provides novel canine pol I regulatory nucleic acid sequences useful for the expression of nucleic acid sequences in canine cells such as MDCK cells. The invention further provides expression vectors and cells comprising such nucleic acids as well as methods of using such nucleic acids to make influenza viruses, including infectious influenza viruses.
1. An isolated nucleic acid comprising a canine RNA polymerase I promoter, wherein the nucleic acid comprises
a polynucleotide comprising the nucleotide sequence set forth in SEQ ID NO:26 or the complement or reverse complement thereof,
wherein the polynucleotide when operably linked to cDNA encoding an influenza vRNA and introduced into a Madin-Darby canine kidney (MDCK) cell is capable of directing the expression of the influenza vRNA.
2. The isolated nucleic acid of claim 1 , wherein the regulatory sequence is operably linked to cDNA encoding a negative-strand viral genomic RNA or the corresponding cRNA.
3. The isolated nucleic acid of claim 2 , wherein the nucleic acid further comprises a transcription termination sequence.
4. The isolated nucleic acid of claim 3 , wherein the negative-strand viral genomic RNA is an influenza genomic RNA.
5. An expression vector comprising the nucleic acid of claim 4 .
6. An isolated cell comprising the expression vector of claim 5 .
7. The isolated cell of claim 6 , wherein the cell is a canine cell.
8. The isolated cell of claim 7 , wherein the canine cell is a kidney cell.
9. The isolated cell of claim 8 , wherein the canine kidney cell is an MDCK cell.
10. The expression vector of claim 5 , wherein the vector comprises the nucleotide sequence set forth as SEQ ID NO:29.
11. An isolated nucleic acid comprising:
(a) a fragment comprising at least 250, or at least 350, or at least 450 contiguous nucleotides of a polynucleotide comprising the nucleotide sequence set forth in SEQ ID NO:26 or the complement or reverse complement thereof, or
(b) a polynucleotide having at least 96% identity to a polynucleotide comprising the nucleotide sequence set forth in SEQ ID NO:26 or the complement or reverse complement thereof.
12. The isolated nucleic acid of claim 11 , wherein the polynucleotide of (a) comprises the 3′ nucleotide of SEQ ID NO:26.
13. The isolated nucleic acid of claim 11 , wherein the polynucleotide of (b) comprises the 3′ nucleotide of SEQ ID NO:26.
14. A vector comprising the nucleic acid of claim 12 .
15. An isolated cell comprising the vector of claim 14 .