Inhibition of apoptosis by Heliothis virescens ascovirus (HvAV-3e): characterization of orf28 with structural similarity to inhibitor of apoptosis proteins.
Ascoviruses (AVs) induce a unique pathology in their insect host cells causing cleavage of the cells into virion-containing vesicles. The mechanism by which AVs induce vesicle formation is poorly understood. It is postulated that the virus initially induces apoptosis leading to cell fragmentation. The apoptotic bodies are however, rescued by the virus to form the vesicles. Here we show that Heliothis virescens AV (HvAV-3e) is able to inhibit chemically induced apoptosis from around 16 h after infection. Analysis of the genome of the virus indicated the presence of a putative inhibitor of apoptosis (orf28) gene that encodes a protein with an imperfect baculovirus inhibitor of apoptosis repeat (BIR) and a RING domain. Transiently expressed orf28 did not inhibit chemically induced apoptosis suggesting that the protein may not serve as an inhibitor of apoptosis. Nevertheless, RNA interference studies revealed that the gene is probably essential for virus pathology and replication.
School of Integrative Biology, University of Queensland, St. Lucia, QLD 4072, Australia.
Mazhar
M
Hussain
Sassan
S
Asgari
D000595:Amino Acid Sequence; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology*; D029223:Ascoviridae / Q000235:genetics / Q000378:metabolism; D016367:Baculoviridae / Q000235:genetics; D002478:Cells, Cultured; D003609:Dactinomycin / Q000378:metabolism; D051034:Inhibitor of Apoptosis Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009036:Moths / Q000821:virology*; D016366:Open Reading Frames; D034622:RNA Interference; D016415:Sequence Alignment; D014779:Virus Replication
D000903:Antibiotics, Antineoplastic; D051034:Inhibitor of Apoptosis Proteins; D003609:Dactinomycin