The role of simian virus 5 V protein on viral RNA synthesis.
The paramyxovirus simian virus 5 (SV5) has seven genes but encodes eight known viral proteins. The V/P gene is transcribed into two mRNA species: V mRNA from a faithful transcription of the gene and P mRNA from transcription with addition of two G residues at a specific site of the gene. V, a 222-amino acid (AA) residue protein, and P, a 392 AA residue protein, share an identical N-terminus domain of 164 amino acid residues. P is essential for SV5 RNA replication and transcription. Whereas it is known that V plays important roles in virus pathogenesis, the role of V in SV5 replication and transcription is not clear. A mini-genome system, free of vaccinia virus gene expression system, consisting of plasmids expressing NP, P, and L, as well as a plasmid encoding a reporter gene, chloramphenicol acetyltransferase (CAT) flanked by SV5 trailer and leader sequences under control of a bacteriophage T7 RNA polymerase promoter, has been established to examine the role of V in SV5 RNA transcription and replication. Addition of V-expressing plasmid in the mini-genome system caused inhibition of the reporter gene expression, suggesting that V plays a role in regulating SV5 gene expression. By examining the amount of encapsidated viral RNA genome using reverse transcription with primer annealing to viral anti-genome RNA and PCR, it was found that expression of V reduced the amount of viral RNA genome in the mini-genome system, suggesting that V inhibits viral RNA replication. To examine whether the V protein inhibits viral RNA transcription as well, a mini-genome system with a defective anti-genome promoter (AGP) such that a reporter gene (luciferase, Luc) expression is only derived from transcription of newly produced mini-genome and not from de novo replicated viral genome due to the defect in replication element has been utilized. The V protein inhibited luciferase expression from the mini-genome with a defective AGP, suggesting V inhibits SV5 transcription. Thus, SV5 V inhibits both SV5 RNA replication and transcription.
Lin
Yuan
Y
Department of Veterinary Science, Pennsylvania State University, University Park, PA 16802, USA.
Horvath
Frank
F
Aligo
Jason A
JA
Wilson
Rebecca
R
He
Biao
B
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D016679:Genome, Viral; D008969:Molecular Sequence Data; D045402:Parainfluenza Virus 5 / Q000235:genetics*; D010957:Plasmids; D012328:RNA Viruses / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014162:Transfection; D015678:Viral Structural Proteins / Q000235:genetics / Q000502:physiology*
D012367:RNA, Viral; C097019:V protein, Simian parainfluenza virus 5; D015678:Viral Structural Proteins