siRNA against the G gene of human metapneumovirus.
BACKGROUND
Human metapneumovirus (hMPV) is a significant viral respiratory pathogen of infants and children, the elderly and immunocompromised individuals. Disease associated with hMPV infection resembles that of human respiratory syncytial virus (RSV) and includes bronchiolitis and pneumonia. The glycosylated G attachment protein of hMPV is required for viral entry in vivo and has also been identified as an inhibitor of innate immune responses.


RESULTS
We designed and validated two siRNA molecules against the G gene using A549 cells and demonstrated consistent 88-92% knock-down for one siRNA molecule, which was used in subsequent experiments. Significant reduction of G mRNA in A549 cells infected with hMPV did not result in a reduction in viral growth, nor did it significantly increase the production of type I interferon (α/β) in response to infection. However, there was a moderate increase in IFN-β mRNA expression in response to infection in siG-transfected cells compared to untransfected and si-mismatch-transfected cells. Expression of G by recombinant adenovirus did not affect type I IFN expression.


CONCLUSIONS
G has been previously described as a type I interferon antagonist, although our findings suggest it may not be a significant antagonist.
Clinical Medical Virology Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
Faith Maxine
FM
Preston
Claire P
CP
Straub
Ruben
R
Ramirez
Suresh
S
Mahalingam
Kirsten M
KM
Spann
D002460:Cell Line; D055785:Gene Knockdown Techniques; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007370:Interferon Type I / Q000096:biosynthesis; D029121:Metapneumovirus / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics*; D014779:Virus Replication
C484233:G glycoprotein, human metapneumovirus; D006023:Glycoproteins; D007370:Interferon Type I; D034741:RNA, Small Interfering; D014764:Viral Proteins