Involvement of reverse transcription in the replication of cauliflower mosaic virus: a detailed model and test of some aspects

Abstract

A model is presented according to which cauliflower mosaic virus (CaMV) DNA is replicated via an RNA intermediate. The model explains the typical S1 nuclease-sensitive sites in mature CaMV DNA, the occurrence of the large, terminally redundant transcript, the local separation of CaMV transcription and CaMV assembly, the abundance of knotted CaMV DNA forms, and the high recombination frequency. A site of perfect homology to plant tRNA was detected. Extracts from a mixture of nuclei and inclusion bodies can be separated into fast-sedimenting complexes elongating endogenous CaMV RNA, and slow-sedimenting ones elongating endogenous CaMV DNA. The CaMV DNA synthesis can be partly inhibited both by RNAase and actinomycin D, suggesting the presence of a mixture of RNA- and DNA-templates.