Enhancement of RNA synthesis in isolated pea nuclei by gibberellic acid.

In many plant tissues, either an increase of protein and RNA synthesis or an increase in the incorporation of labeled precursors into these macromolecules in the target tissue is evoked by hormones.'-6 A few reports indicate that hormones may also enhance the RNA synthesis by isolated nuclei.7-'0 It has in no case been shown that the increased RNA synthesis is a primary effect of the hormone, as opposed to a secondary or derivative effect. Nor has it been shown whether or not the RNA synthesized by the hormone-treated nuclei is qualitatively different from that synthesized by the control nuclei. Because lightgrown dwarf peas respond to exogenous gibberellins, we decided to study possible hormone-nuclei interactions by treating isolated nuclei of dwarf peas with gibberellic acid (GA). The results show that GA can interact with cell homogenates and modify RNA synthesis by nuclei. GA-treated nuclei not only synthesize more RNA than the control nuclei, but also the RNA has a nearest-neighbor frequency different from the RNA from control nuclei. The response is discernible only if the nuclei are isolated in the presence of hormone. The lack of response in the nuclei isolated in the absence of hormone is probably due to loss of a factor (or factors) during isolation.