TY - JOUR
T1 - A single amino acid residue change in the P protein of parainfluenza virus 5 elevates viral gene expression
AU - Timani, Khalid A.
AU - Sun, Dengyun
AU - Sun, Minghao
AU - Keim, Celia
AU - Lin, Yuan
AU - Schmitt, Phuong Tieu
AU - Schmitt, Anthony P.
AU - He, Biao
PY - 2008/9
Y1 - 2008/9
N2 - Parainfluenza virus 5 (PIV5) is a prototypical paramyxovirus. The V/P gene of PIV5 encodes two mRNA species through a process of pseudotemplated insertion of two G residues at a specific site during transcription, resulting in two viral proteins, V and P, whose N termini of 164 amino acid residues are identical. Previously it was reported that mutating six amino acid residues within this identical region results in a recombinant PIV5 (rPIV5-CPI-) that exhibits elevated viral protein expression and induces production of cytokines, such as beta interferon and interleukin 6. Because the six mutations correspond to the shared region of the V protein and the P protein, it is not clear whether the phenotypes associated with rPIV5-CPI- are due to mutations in the P protein and/or mutations in the Y protein. To address this question, we used a minigenome system and recombinant viruses to study the effects of mutations on the functions of the P and Y proteins. We found that the P protein with six amino acid residue changes (Pcpi-) was more efficient than wild-type P in facilitating replication of viral RNA, while the V protein with six amino acid residue changes (Vcpi-) still inhibits minigenome replication as does the wild-type V protein. These results indicate that elevated viral gene expression in rPIV5-CPI- virus-infected cells can be attributed to a P protein with an increased ability to facilitate viral RNA synthesis. Furthermore, we found that a single amino acid residue change at position 157 of the P protein from Ser (the residue in the wild-type P protein) to Phe (the residue in Pcpi-) is sufficient for elevated viral gene expression. Using mass spectrometry and 33P labeling, we found that residue S157 of the P protein is phosphorylated. Based on these results, we propose that phosphorylation of the P protein at residue 157 plays an important role in regulating viral RNA replication.
AB - Parainfluenza virus 5 (PIV5) is a prototypical paramyxovirus. The V/P gene of PIV5 encodes two mRNA species through a process of pseudotemplated insertion of two G residues at a specific site during transcription, resulting in two viral proteins, V and P, whose N termini of 164 amino acid residues are identical. Previously it was reported that mutating six amino acid residues within this identical region results in a recombinant PIV5 (rPIV5-CPI-) that exhibits elevated viral protein expression and induces production of cytokines, such as beta interferon and interleukin 6. Because the six mutations correspond to the shared region of the V protein and the P protein, it is not clear whether the phenotypes associated with rPIV5-CPI- are due to mutations in the P protein and/or mutations in the Y protein. To address this question, we used a minigenome system and recombinant viruses to study the effects of mutations on the functions of the P and Y proteins. We found that the P protein with six amino acid residue changes (Pcpi-) was more efficient than wild-type P in facilitating replication of viral RNA, while the V protein with six amino acid residue changes (Vcpi-) still inhibits minigenome replication as does the wild-type V protein. These results indicate that elevated viral gene expression in rPIV5-CPI- virus-infected cells can be attributed to a P protein with an increased ability to facilitate viral RNA synthesis. Furthermore, we found that a single amino acid residue change at position 157 of the P protein from Ser (the residue in the wild-type P protein) to Phe (the residue in Pcpi-) is sufficient for elevated viral gene expression. Using mass spectrometry and 33P labeling, we found that residue S157 of the P protein is phosphorylated. Based on these results, we propose that phosphorylation of the P protein at residue 157 plays an important role in regulating viral RNA replication.
UR - http://www.scopus.com/inward/record.url?scp=50949129848&partnerID=8YFLogxK
U2 - 10.1128/JVI.00289-08
DO - 10.1128/JVI.00289-08
M3 - Article
C2 - 18614634
AN - SCOPUS:50949129848
SN - 0022-538X
VL - 82
SP - 9123
EP - 9133
JO - Journal of Virology
JF - Journal of Virology
IS - 18
ER -