The F protein of Helicoverpa armigera single nucleopolyhedrovirus can be substituted functionally with its homologue from Spodoptera exigua multiple nucleopolyhedrovirus.
F proteins of group II nucleopolyhedroviruses (NPVs) are envelope fusion proteins essential for virus entry and egress. An F-null Helicoverpa armigera single nucleocapsid NPV (HearNPV) bacmid, HaBacDeltaF, was constructed. This bacmid could not produce infectious budded virus (BV) when transfected into HzAM1 cells, showing that F protein is essential for cell-to-cell transmission of BVs. When HaBacDeltaF was pseudotyped with the homologous F protein (HaBacDeltaF-HaF, positive control) or with the heterologous F protein from Spodoptera exigua multinucleocapsid NPV (SeMNPV) (HaBacDeltaF-SeF), infectious BVs were produced with similar kinetics. In the late phase of infection, the BV titre of HaBacDeltaF-SeF virus was about ten times lower than that of HaBacDeltaF-HaF virus. Both pseudotyped viruses were able to fuse HzAM1 cells in a similar fashion. The F proteins of both HearNPV and SeMNPV were completely cleaved into F(1) and F(2) in the BVs of vHaBacDeltaF-HaF and vHaBacDeltaF-SeF, respectively, but the cleavage of SeF in vHaBacDeltaF-SeF-infected HzAM1 cells was incomplete, explaining the lower BV titre of vHaBacDeltaF-SeF. Polyclonal antisera against HaF(1) and SeF(1) specifically neutralized the infection of vHaBacDeltaF-HaF and vHaBacDeltaF-SeF, respectively. HaF(1) antiserum showed some cross-neutralization with vHaBacDeltaF-SeF. These results demonstrate that group II NPV F proteins can be functionally replaced with a homologue of other group II NPVs, suggesting that the interaction of F with other viral or host proteins is not absolutely species-specific.
Wang
Manli
M
Graduate School of the Chinese Academy of Sciences, Beijing 100039, PR China.|State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
Tan
Ying
Y
Graduate School of the Chinese Academy of Sciences, Beijing 100039, PR China.|State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
Yin
Feifei
F
Graduate School of the Chinese Academy of Sciences, Beijing 100039, PR China.|State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
Deng
Fei
F
State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
Vlak
Just M
JM
Laboratory of Virology, Wageningen University, 6709 PD Wageningen, The Netherlands.
Hu
Zhihong
Z
State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
Wang
Hualin
H
State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China.
D000818:Animals; D002459:Cell Fusion; D002478:Cells, Cultured; D015726:Giant Cells / Q000502:physiology; D009036:Moths / Q000821:virology*; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D011995:Recombination, Genetic; D013045:Species Specificity; D018411:Spodoptera / Q000821:virology*; D014162:Transfection; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D014760:Viral Fusion Proteins