Abstract
Core promoter plays a crucial role in determining the transcription initiation site. Recent studies revealed that the diversity of its architecture is sometimes involved in the gene-specific transcriptional regulation. Generally, core promoters are composed of modules, such as TATA box and initiator element, the latter of which covers the transcription initiation site (+1), and has a weak consensus motif in mammalian genes. However, we still have limited knowledge about the transcription initiation signals operative in the plant genome. In this study, we carried out a systematic survey of the plant transcription initiation signals in in vitro transcription systems, with special reference to the tri-nucleotides covering the transcription initiation site (-1 to +2). Possible 64 combinations of the tri-nucleotides were subjected to this analysis in the nuclear extracts from both tobacco and Hela cells. The obtained results revealed the unexpected feature of the transcription initiation signals in the plant genome.
