Multiple nuclear protein binding to 135 bp subrepeat element of wheat ribosomal DNA intergenic spacer

Specific binding of wheat nuclear proteins to 135 bp subrepeat element of the ribosomal DNA intergenic spacer was studied by electrophoretic mobility shift assays. A number of specific DNA-protein complexes are readily formed upon incubation of the labelled 135 bp subrepeat element with wheat nuclear protein extracts. Some of these complexes have various DNA-binding specificities as evidenced by their optimal detection in the presence of different non-specific competitor polynucleotides. One of the wheat nuclear proteins was found to bind specifically both to 135 bp subrepeat element and an intergenic spacer region located downstream of the transcription initiation site (between +192 and +366 bp). No apparent effects of the 135 bp element methylation with methylase HpaII on protein binding were found.