Altered chromatin conformation of the higher plant gene phaseolin

Micrococcal nuclease, DNase I, and S1 nuclease were used to probe alterations in the chromatin conformation of phaseolin genes which encode the major seed storage proteins of the French bean (Phaseolus vulgaris L. cv. Tender-green). Comparisons were made between cotyledon tissue where the genes are expressed and leaf tissue where the genes are not expressed. Phaseolin genes are preferentially sensitive to DNase I in cotyledons relative to leaves. DNase I hypersensitive sites could not be identified in the flanking DNA of phaseolin genes in chromatin. Although S1 nuclease hypersensitive sites could be identified in DNA sequences flanking the phaseolin genes when analysis was performed on pure, supercoiled DNA, they could not be demonstrated in chromatin.