Hairpin DNAs of cauliflower mosaic virus generated by reverse transcription in vivo

Abstract

Cauliflower mosaic virus (CaMV) is a DNA plant virus which replicates by reverse transcription. During examn. of CaMV replication intermediates by 2-dimensional gel electrophoresis, a population of bizarre linear double-stranded hairpin DNAs was discovered. The largest hairpin is the size of the CaMV genome; hairpin loop ends of smaller mols. map to several sites around the genome, but the open ends are all located close to the origin of reverse transcription at the primer binding site. The hairpin DNAs are probably generated in vivo by reverse transcription of CaMV RNA followed by self-primed 2nd strand synthesis. The accumulation of hairpin DNAs in vivo might represent a side reaction of the CaMV reverse transcriptase, although an essential role for them in the virus replication cycle cannot be discounted. The structure of the hairpin DNAs provides further evidence for the location of the start site and of the polarity of reverse transcription in CaMV. [on SciFinder(R)]