Transcription of the cauliflower mosaic virus genome in isolated nuclei from turnip leaves.

Nuclei isolated from turnip (Brassica rapa L. c.v. Just Right) leaves infected with cauliflower mosaic virus synthesize RNA in vitro which hybridizes to purified cauliflower mosaic virus DNA. Nuclei isolated from uninfected leaves do not produce these viral transcripts in vitro. Viral-specific transcription in isolated nuclei is catalyzed by endogenous DNA-dependent RNA polymerase 11 based on sensitivity to alpha-amanitin and ionic strength optima. Only one strand of the viral genome is transcribed in vitro in isolated nuclei. The RNA synthesized in vitro hybridizes to the same strand and EcoRI restriction fragments of cauliflower mosaic virus DNA as the viral-specific RNA that accumulates in vivo in infected turnip leaves.