Investigation of the transfection capability of cloned tandemly-repeated chicken anaemia virus DNA fragments.
Chicken anaemia virus (CAV) is an icosahedral virus, 25 nm in diameter, which, on the basis of its circular single-stranded DNA genome, has recently been classified in the family, Circoviridae. We have investigated whether infectious, monomeric CAV DNA from recombinant plasmids containing tandemly-repeated CAV replicative form (RF) DNAs, following transfection, was generated by homologous recombination or a replicational release mechanism involving rolling circle replication (RCR) of DNA. Experiments designed to locate the virus strand origin of RCR and/or sites of recombination were performed by sequence analyses of hybrid viruses generated after transfection with cloned tandemly-repeated RFs specified by the sequence-distinct Cux-1 and 26P4 isolates. Positive transfection results obtained from 2 recombinant plasmid constructs were shown to have resulted from homologous recombination occurring at different sites within the RF sequence. Three of 5 hybrid viruses analysed were "circularised" within the same 105 bp sequence, that contains four 19bp repeats and with which promoter/enhancer activity has been associated. This region may represent a novel origin or recombination hot-spot within the CAV genome. A distinctive cruciform-loop structure within the non-coding region was shown to contain an S1 nuclease-sensitive site, detected in CAV RF and in recombinant plasmids containing RF inserts.
Todd
D
D
Department of Agriculture for Northern Ireland.
Creelan
J L
JL
Meehan
B M
BM
McNulty
M S
MS
D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017727:Chicken anemia virus / Q000235:genetics*; D003001:Cloning, Molecular; D053938:DNA Fragmentation; D004279:DNA, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D014162:Transfection
D004279:DNA, Viral; D015719:Single-Strand Specific DNA and RNA Endonucleases