ACCURATE INVITRO TRANSCRIPTION OF PLANT PROMOTERS WITH NUCLEAR EXTRACTS PREPARED FROM CULTURED PLANT-CELLS

A simple method is presented for the preparation of nuclear extracts from suspension cultures of rice, wheat and tobacco cells. These extracts are shown to be capable of RNA Polymerase II-dependent transcription from two plant promoters in vitro; a 250 bp fragment of a wheat gliadin promoter containing sequences from - 167 bp to + 83 relative to the in vivo transcriptional initiation site and two fragments of the CaMV 35S promoter, containing sequences from - 419 to + 17, and from - 90 to + 17. Using the rice extract, transcription is shown to be extract-dependent, DNA-dependent, alpha-amanatin-sensitive, promoter-dependent, and accurate with respect to initiation site selection on the gliadin promoter and the - 90 to + 17 35S promoter, but not accurate on the - 419 to + 17 35S promoter.