Abstract
We evaluated the degree of chromatin condensation around the HSP18.2, H4, PCNA, V-ATPase and ADH gene promoters in Arabidopsis plants and suspension cells. The DNase I sensitivities were at a similar level between these genes and among leaves and suspensions irrespective of their expression states, however the local DNase I hyper-sensitive sites (HS sites) were found at the every promoter except the ADH gene at the same position in leaves as well as in suspension cells. The nucleosome positioning around the HS site was changed by heat activation in HSP18.2 promoter. Furthermore, at the ADH promoter the HS site is found in suspension cells but not in leaves, and the ADH gene is induced by ABA in suspensions but not in leaves. Taken together, it is suggested that these HS sites are involved in gene regulation by controlling the accessibility of transcription factors to the promoter.
