| The ie0 gene is a late gene of Bombyx mori nucleopolyhedrovirus(BmNPV),the highly conserved amino acid sequence which was encoded by ie0 gene and multiple domains showed the importance of ie0 gene in the process of virus infection.By red homologous recombination technology,different types of deficient-virus were constructed to study its effect on virus replication? transcription and host cell infection ?apoptosis,including the deficiency of four different domains which was encoded by BmNPV ie0 gene and the whole gene,respectively,and using wild type virus as control.The results showed that the ie0 gene or the four sequences which encoded each domains was deleted would have different effect on virus: in host cells,virus titers of complete-deletion-type and partial-deletion-type virus were decreased in different degrees;genome copy number of complete-deletion-type and partial-deletion-type virus had no significant difference when compared with wild type virus;consistent with complete-deletion virus late and very late gene transcription levels in partial-deletion-type virus were significantly lower than wild type virus,and the influence of zinc finger domain is the most obvious domain.MTT results also showed that the whole gene deletion would lead to the decrease of virus pathogenic ability in host cells.Western blotting results showed that the expression level of apoptosis inhibiting gene Bcl-2had no no significant changing in host cells which was infected by complete-deletion of ie0,while the expression level of pro apoptosis gene Bax was down-regulated.And the subcellular localization experiment showed that the IE0 protein was mainly located in cytoplasm although it was distributed in cytoplasm and nucleus.In summary,ie0 gene is inessential for BmNPV proliferation,genome replication,but it plays an important role in the control of the virus genome transcription process,especially the zinc finger domain,and the ie0 deficiency will also lead to a decline of host cell apoptotic level. |
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