Effect of RNA Inhibitors on Mitosis inPleurodelesLung Cells

Abstract

SUMMARYIn primary cultures of Pleurodeles lung cells, the dependency of mitotic development on RNA synthesis was studied by means of several drugs, which have in common the inhibition of RNA synthesis (Actinomycin D, 3'Deoxyadenosine, Ethidium bromide, Acridine orange and Proflavine hemi-sulfate).All of the inhibitors used have shown themselves capable, at certain concentrations, of inhibiting prophase development, while they do not affect quality or quantity-wise the course from prometaphase to telophase.In a similar way, all the inhibitors completely blocked the telophase reorganization of the nucleoli, and the concentrations necessary to inhibit this process did not affect at all the normal course and duration of the different mitotic periods. We observed the most spectacular case with Actinomycin-D where the telophasic reorganization of the nucleolus was already inhibited by 2 ug/ml while prophase development was affected only after 25 ug/ml.