J. Paul, R. Reynolds, P. Montgomery
Mar 1, 1969
Citations
0
Influential Citations
7
Citations
Quality indicators
Journal
Cancer research
Abstract
Summary 4-Nitroquinoline- N -oxide, a potent mutagenic, carcinogenic, and carcinostatic agent, has been studied with respect to its effects on RNA synthesis using sucrose gradients, methylated albumin Kieselguhr columns, and the electron microscope. An analysis of polyribosomal amino acid incorporation in tissue culture systems exposed to 4-nitroquinoline- N -oxide demonstrated a marked inhibition of the incorporation of amino acids by polyribosomal structures; the inhibition of amino acid incorporation was apparent within one hour after exposure to 4-nitroquinoline- N -oxide. A few hours after the addition of 4-nitroquinoline- N -oxide, increased amounts of low molecular weight RNA could be demonstrated by trichloracetic acid extraction or methylated albumin Kieselguhr chromatography. This increase probably represented active synthetic products and was not derived primarily from degraded RNA of higher molecular weight. Exposure of HeLa cells to 4-nitroquinoline- N -oxide for 24 hours resulted in depressed synthesis in all RNA fractions; RNA sedimenting below 10 S was less depressed than heavier RNA fractions, as evaluated by sucrose density gradient centrifugation. The similarity between RNA synthesis in the presence of 4-nitroquinoline- N -oxide and actinomycin D in low dosages is discussed, and the possible similarities in the sites of action are described.