摘要
The spheroidin genes of Calliptamus italicus entomopoxvirus (CiEPV) and Gomphocerus sibiricus entomopoxvirus (GsEPV) were obtained by PCR,and the fragments were cloned, sequenced and analyzed. The CiEPV and GsEPV spheroidin genes respectively harbored ORFs of 2 922 bps and 2 967 bps that were capable of coding polypeptides of 109.2 and 111.1 kDa. Computer analysis indicated that CiEPV and GsEPV spheroidins shared less than 20% amino acid identities with lepidopteran AmEPV and coleopteran AcEPV spheroidins, but more than 80% amino acid identities with orthopteran OaEPV, MsEPV and AaEPV spheroidins. The CiEPV and GsEPV spheroidins respectively contained 19 and 21 cysteine residues that were particularly abundant at the C-termini, as is the case with those of the other orthopteran EPV spheroidins. The numbers and locations of the cysteine residues of the spheroidins were most similar to those of the spheroidins of EPVs that are virulent on the same insect orders. The promoter regions of the two spheroidin genes were highly conserved (99%) among the orthopteran EPVs and also contained the typical very A+T rich and TAAATG signal mediating transcription of poxvirus late genes. We also sequenced an incomplete ORF downstream of the pheroidin gene of CiEPV and GsEPV. The ORF was in the opposite direction to the spheroidin gene and was homologous to MSV072 putative protein of MsEPV.
