Inhibition of ribonuclease activity during RNA synthesis in isolated yeast nuclei by cadmium.

We have developed an efficient transcription system in isolated yeast nuclei. If MnCl2 is substituted by CdCl2, degradation of newly synthesized RNA is markedly reduced. This effect is due to the inhibition of nuclear ribonuclease activity, since microsomal ribonuclease activity is less affected by the cation. The extent to which the addition of CdCl2 to the in vitro transcription assay inhibits ribonuclease activity is demonstrated by the measurements of the size of newly synthesized RNA. Efficient RNA synthesis in this system is not affected up to a concentration of 0.1 M CdCl2.