Abstract
Chromatin-bound DNA-dependent RNA polymerases react upon wounding of white potato tuber tissues with an increase in activity, which is additionally enhanced to 300% in the presence of 0.1 micromolar gibberellic acid (GA(3)). 2,4-Dichlorophenoxyacetic acid is only weakly effective and indoleacetic acid not at all. Wounding and treatment with GA(3) affect template availability of chromatin only slightly. The hormone has no effect on chromatin-bound RNA polymerases, if added in vitro.The enzymes from intact, wounded, and hormone-treated tissues possess similar characteristics: their activity is dependent on the presence of all four ribonucleotides and a divalent cation such as Mg(2+) or Mn(2+). However, the sensitivity of the enzymes from different preparations toward alpha-amanitin differs. Total RNA polymerase activity of chromatin was inhibited by alpha-amanitin to about 44% in intact, to about 22% in wounded, and only 15% in GA(3)-treated tissues. The relative activities of polymerases I and II were estimated by varying the (NH(4))(2)SO(4) and alpha-amanitin concentrations in the assay system. It is evident that GA(3) preferentially stimulates polymerase I and hence ribosomal RNA synthesis. RNA polymerase II is but slightly affected by GA(3). Nearest neighbor frequency analysis revealed that the RNA synthesized by the enzymes from the intact tuber is different from that of wounded or GA(3)-treated tissues.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.