Maedi-visna virus (MVV) preferrentially integrates into genes and generates 6-bp duplications

We sequenced MVV integration sites in acutely infected primary sheep cells and compared them to a control set of integration sites generated using recombinant MVV intasomes and deproteinized genomic sheep DNA. Alignment of the integration sites revealed symmetric sequence preferences that are consistent with integration of viral ends across 6 bp in target DNA in both conditions. As expected for a lentivirus, MVV displayed a strong preference for transcription units, with 70.2% integration sites found within predicted sheep genes, compared to 43.7% in the in vitro generated control condition. Overall design: Integration sites obtained by infection of sheep choroid plexus cells with pathogenic MVV strain KV1772 or by incubation of deproteinised sheep DNA with recombinant intasome (in vitro control condition) were amplified by linker-mediated PCR and sequenced using Illumina technology.