Characterization of Campoletis sonorensis ichnovirus unique segment B and excision locus structure

摘要: Abstract Polydnaviruses (PDVs) are segmented, symbiotic, double-stranded DNA viruses that vertically transmitted as proviruses within the genomes of some parasitoid Hymenoptera. The PDV associated with ichneumonid wasp Campoletis sonorensis (CsIV) consists 24 non-redundant segments varying in size from ~6 to 20 kbp. CsIV segment B, one smallest genome segments, was sequenced and excision sites proviral were characterized. B sequence 83.2% non-coding only two open reading frames (ORFs). Some sequences have similarities database likely pseudogenic, but most unrelated known nucleic acid or predicted protein sequences. One ORF, BHv0.9, encodes a member rep gene family expressed parasitized insects while transcription other ORF could not be detected. Previously, third region shown hybridize 0.6 1.2 kb poly A+ RNAs female wasps during virus replication ( Theilmann Summers, 1988 ) this did an identifiable determined sequence. In contrast W, had little repetitive integration locus contains 59 bp direct imperfect repeat. Further analyses demonstrated excised genomic flanking at site rejoined after excision. ‘excision locus’ retained copies repeat present segment. data indicate Ichnovirus distinctive characteristics possibly reflecting functional co-evolution between individual types polydnavirus segments.