6-Methylpurine-H3: intracellular localization in pea root tip cells

6-Methylpurine-H3, a potent inhibitor, was detected by autoradiography in the nucleoli of pea root tip cells. Most of the radioactivity was in the nucleoli of growing cells in the meristematic region. Treatment of the labeled cells with ribonuclease indicates that 6-methylpurine-H(3) is incorporated into nucleolar RNA which then moves from the nucleolus to the cytoplasm.