Effect of puromycin on RNA synthesis in HeLa cells

Abstract

Sedimentation analyses of RNA from HeLa cells have revealed that rapidly-labeled RNA sediments faster in a sucrose gradient than ribosomal RNA ( Scherrer and Darnell, 1962). This RNA fraction is confined to the nucleus and its synthesis is prevented by a low level (0.01 μg/ml) of actinomycin D ( Tamaoki and Mueller, 1962). Recent papers by Perry (1963) and Scherrer et al. (1963) indicate that at least two kinds of RNA are present in the rapidly sedimenting fraction: (1) a precursor RNA which converts into ribosomal RNA in the presence of actinomycin D, and (2) DNA-like RNA which is capable of forming a hybrid with HeLa cell DNA and stimulates amino acid incorporation in a cell-free E. coli system. In this paper, the effect of puromycin on RNA metabolism in HeLa cells will be presented. The data illustrate that the synthesis and turnover of a fraction of the heavy RNA continued in the presence of puromycin, whereas the introduction of guanine-8-C 14 into other classes of RNA (28 and 16s) was blocked by puromycin.