Generating a host range-expanded recombinant baculovirus

Abstract

As baculoviruses usually have a narrow insecticidal spectrum, knowing the mechanisms by which they control the host-range is prerequisite for improvement of their applications as pesticides. In this study, from supernatant of culture cells transfected with DNAs of an Autographa californica multiple nucleopolyhedrovirus (AcMNPV) mutant lacking the antiapoptotic gene p35 (vAc∆P35) and a cosmid representing a fragment of Spodoptera exigua nucleopolyhedrovirus (SeMNPV), a viral strain was plaque-purified and named vAcRev. vAcRev had a broader host range than either vAc∆P35 or SeMNPV parental virus, being able to infect not only the permissive hosts of its parental viruses but also a nonpermissive host (Spodoptera litura). Genome sequencing indicated that vAcRev comprises a mixture of two viruses with different circular dsDNA genomes. One virus contains a genome similar to vAc∆P35, while in the other viral genome, a 24.4 kbp-fragment containing 10 essential genesis replaced with a 4 kbp-fragment containing three SeMNPV genes including a truncated Se-iap3 gene. RNA interference and ectopic expression assays found that Se-iap3 is responsible for the host range expansion of vAcRev, suggesting that Se-iap3 inhibits the progression of apoptosis initiated by viral infection and promotes viral propagation in hosts both permissive and non-permissive for AcMNPV and SeMNPV.

Genomic sequencing of Troides aeacus nucleopolyhedrovirus (TraeNPV) from golden birdwing larvae (Troides aeacus formosanus) to reveal defective Autographa californica NPV genomic features

“…Baculoviruses usually showed high specificity to a few, or even individual, insect species [68, 69]. For this reason, a variety of efforts has been made to understand the baculoviral genes that are related to their host range.…”

Baculovirus PTP2 Functions as a Pro-Apoptotic Protein

“…Baculoviruses are known to produce anti-apoptotic proteins (e.g., P35 and IAP) to suppress or delay apoptosis [ 15 ]. For example, besides SePTP2, SeMNPV also encodes the anti-apoptotic proteins IAP2 and IAP3 [ 17 , 18 ]. However, anti-apoptotic and pro-apoptotic genes may function via different pathways.…”

“…SeMNPV possesses iap2 and iap3 homologues [ 16 ]. SeMNPV IAP3 was able to block chemical induction of apoptosis in insect cells and mammalian cells; however, the function of iap2 is not known yet [ 17 , 18 ].…”

Baculovirus-induced insect behaviour: from genes to brains

“…Baculoviruses are known to produce anti-apoptotic proteins (e.g., P35 and IAP) to suppress or delay apoptosis (Clem, 2001). For example, besides SePTP2, SeMNPV also encodes the antiapoptotic proteins IAP2 and IAP3 (Wu et al, 2016;Zhu et al, 2008). However, anti-apoptotic and pro-apoptotic genes may function via different pathways.…”

“…SeMNPV IAP3 was able to block chemical induction of apoptosis in insect cells and mammalian cells; however, the function of iap2 is not known yet (Wu et al, 2016;Zhu et al, 2008 (Patterson et al, 2009). Here, we tested whether SeMNPV PTP2 has a similar function to the MdBV PTP-H2 in inducing apoptosis in its host.…”