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Helicoverpa Armigera Nuclear Polyhedrosis Virus Iap2 Gene Cloning, Sequencing And Prokaryotic Expression Of Helicoverpa Armigera Nuclear Polyhedrosis Virus Fragment Of Bam H-if Sequence Analysis

Posted on:2002-12-24Degree:MasterType:Thesis
Country:ChinaCandidate:X X ZhangFull Text:PDF
GTID:2193360032453614Subject:Biochemistry and Molecular Biology
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There are three chapters in this thesis.In chapter one there is a detailed sequence analysis and comparison of conserved region of iap2 gene of HaSNPV.Sequence analysis revealed that iap2 gene of HaSNPV is locatedin BamH I 桭 fragment of HaSNPV genome. Nucleotide sequencing showed the open reading frame was 753 nt, encoded 250 amino acids with a predicted size of 29.2kD. A 揟ATA?box was found?0 ?3nt upstream of the translational start codon ATG. There is an early consensus translational motif CAAT, ?0 ?-53nt upstream of the translational start codon ATG. A typical poly(A) signal was identified 46 ?5lnt downstream of the translational stop codon TAA. HaSNPV iap2 gene encode onetypical RING and two BIRs. The alignment of AcMNPV~. OpMNPV~ LdMNPV~ SeNNPV~ DIAP and XIAP indicated that they hadconserved BIR and RING zinc finger motifs. It was suggested HaNPV IAP2 had a potential anti-apoptotic function.In order to study the IAP2抯 structure and region, in chapter two we constructed an express vector of iap2 gene, further more, we expressed IAP2 protein in differect conditions to improve the condition of induced expression in prokaryotic cell. The result indicated that iap2 gene has been ligated with express vector pET?8a successfully. There was an about 3OKda unique band in SDS-PAGE gel, whose molecular was consisited to that of deduced IAP2 protein.In chapter three there is detailed sequence analysis and comparision of conserved region of leff-3 gene, DNA polymerase2HaSNPV BamH I 桭Ij~Ji~ iap2 ~~jliJf~gene and hr3. The results are:HaSNPV DNA polymerase gene include a unique 揂CG?repeat sequence , which is different from other bacloviruses. This indicate that HaSNPV DNA polymerase gene probably has a new transcriptional origion.Lef-3 gene is an essential factor for the expression of late gene. LEE?3 protein of AcMNPV, OpMNPV and SeMNPV were proved to be SSBs. HaSNPV LEF-3 protein also has the conserved motif, which exists in nearly 20 kinds of SSBs, so HaSNPV LEF-3 protein is a probable SSB protein.The palindrome and direct repeat sequence of HaSNPV hr3 does not have homerlogous sequence in other baculoviruses,what抯 more, the palindrome of this hr3 has an Mul I siteinstead of an EcoR I site, which indicated HaSNPV genome ptobably possessed a new kind of conserved sequence for DNA replication.
Keywords/Search Tags:Polyhedrosis
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