Effects of polyamines and methylglyoxal bis(guanylhydrazone) on Escherichia coli ribonucleic acid polymerase and the template activity of hepatic cell nuclei in vitro.
Escherichia coli RNA polymerase was assayed with 4 mM Mg2+ and 1 mM Mn2+ using native DNA, heat-denatured DNA, histone-nucleate and isolated rat liver nuclei as the template source. With purified DNA and either or both divalent metal ions, 0.1--5 mM amine stimulated enzyme activity. Spermidine resulted in the greatest stimulation (1.7-fold at 5 mM); whereas, spermine or methylglyoxal bis(guanylhydrazone) first stimulated, then above 3 mM inhibited, the reaction. The addition of unfractionated histone to purified DNA inhibited the reaction by 90%. The subsequent addition of amines resulted in a slight stimulation in incorporation (1.5-fold) in the range of 1--3 mM amine. Alternatively, when enzyme was combined with DNA before histone, only a 20% inhibition was observed and this could be completely prevented by 3 mM spermidine. The addition of amines to isolated nuclei resulted in marked alterations in ultrastructure and Mg2+ content; however, relatively small effects on RNA polymerase activity were observed. With the E. coli enzyme, 0.1--1.0 mM amine stimulated RNA synthesis (1.5-fold) whereas, none of the amines stimulated endogeneous activity in the absence or presence of 300 mM (NH4)2SO4.
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004789:Enzyme Activation; D006146:Guanidines / Q000494:pharmacology*; D006657:Histones / Q000494:pharmacology; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008345:Manganese / Q000494:pharmacology; D008935:Mitoguazone / Q000494:pharmacology*; D011073:Polyamines / Q000494:pharmacology*; D051381:Rats; D013698:Templates, Genetic
D006146:Guanidines; D006657:Histones; D011073:Polyamines; D008345:Manganese; D012321:DNA-Directed RNA Polymerases; D008274:Magnesium; D008935:Mitoguazone