An intrinsically bent region upstream of the transcription start site of the rRNA genes of Arabidopsis thaliana interacts with an HMG-related protein.

Intrinsically bent DNA structures are thought to play crucial roles as functionally important modules in promoter/enhancer elements. Here we show the existence of a DNA bending centre within the intergenic region of the tandemly arranged rRNA genes of Arabidopsis thaliana. By use of a circular permutation assay, this bending centre was localized to position -284 to -256 upstream of the transcription start site. A 143 bp fragment containing the bent region was shown to interact with several nuclear proteins. Evidence is presented that one of these proteins is related to the high-mobility-group (HMG) proteins, a group thought to be involved in transcription and replication processes.