Expression And Function Analysis Of Inhibitor Of Apoptosis Protein From Antheraea Pernyi Nucleopolyhedrovirus

Baculoviral inhibitor of apoptosis protein (IAP) plays an important role in apoptosis. But the target protein and the mechanism are still unclear. The Chinese oak silkworm Antheraea pernyi (A.pernyi) is an important economic insect. The quantity and quality of A.pernyi are directly affected by the infection of Antheraea pernyi multicapsid nucleopolyhedrovirus (ApMNPV). ApMNPV encodes two possible inhibitor of apoptosis protein (Ap-IAP1 and Ap-IAP2). Their nature, function and role on antiviral mechanism are unknown. In the present study, functional analysis of two Ap-IAPs on anti-apoptosis was done in detail by using transcription analysis of gene expression,protein interactions in vitro and RNA interference. (1)We assay the 5’and 3’ non-coding region of Ap-iapl and Ap-iap2.Then,we found that ApMNPV can infect TnHi-5 and express EGFP.Ap-iap1 and Ap-iap2 transcribe in the virus infection early, but transcriptional expression level lower than DNA pol. (2)Both of Ap-IAP1 and Ap-IAP2 expressed in vitro have protein binding characteristics. Not only Ap-IAP1 but also Ap-IAP2 interactions with Ap-IAP1 each other. (3)Caspase-3-like protease activity of Tn-Hi5 cells induced with actinomycin-D was able to be suppressed by ApMNPV△ph/egfp+ infection.The results of RNAi showed that silencing of Ap-iap1 repressed the ability of ApMNPV on anti-apoptosis in TnHi-5, and reduced the transcription of Ap-iap2 and DNA pol Silencing of Ap-iap2 repressed the transcription of Ap-iapl and DNA pol. Overall, these results indicate that Ap-IAP1 play a role in ApMNPV anti-apoptosis. Ap-IAP2 participates in ApMNPV anti-apoptosis. Ap-IAP1 and Ap-IAP2 are relationship with each other, although their functions are different. Both of Ap-IAP1 and Ap-IAP2 can effect DNA pol expression. Ap-iapl and Ap-iap2 are not essential for ApMNPV. We not only systematic analyzed the Ap-IAP1 and Ap-IAP2 on their properties and anti-apoptotic function, also found their role in virus replication and leads of their target for further study. These results provide the first evidence for study on the antiviral mechanism and breeding of A.pernyi.