Novel in vitro transcription assay indicates that the accD NEP promoter iscontained in a 19 bp fragment

In order to characterize promoters for the nuclear-encoded plastid RNA poly merase (NEP), we developed a novel in vitro transcription system. The assay is based on extracts from plants lacking the plastid-encoded RNA polymeras e (PEP) activity due to targeted deletion of the PEP alpha subunit gene. We report here the characterization of PaccD-129, the promoter for accD, enco ding a subunit of the acetyl-CoA carboxylase. Dissection of a similar to 0. 8 kb fragment determined that the accD promoter is contained within a 19-bp fragment (-17/+2).