Chromatin- and Nuclei-Directed Ribonucleic Acid Synthesis in Sugar Beet Root

The synthesis of RNA by chromatin-bound RNA polymerase prepared from sugar beet (Beta vulgaris) root tissue is completely dependent on the presence of a divalent metal (Mg(2+) or Mn(2+)) and the presence of four ribonucleoside triphosphates. Accumulation of labeled acid-insoluble product is inhibited by the addition of RNase and actinomycin D to the reaction. When beet root slices are washed for 25 hours, chromatin-associated RNA polymerase activity increases 7-fold over that of unwashed tissue. This enzyme activity declines with further washing. DNA template availability, as measured by saturating levels of added Escherichia coli RNA polymerase, was also found to follow a pattern similar to that for RNA polymerase. Nearest neighbor frequencies of the RNA synthesized by chromatin isolated from unwashed and washed tissue are different.Washing tissue in solutions of gibberellic acid and auxin enhances template availability of the isolated chromatin. Experiments with isolated nuclei indicate an effect of these hormones on RNA synthesis.