The effect of nicotinamide on unscheduled DNA synthesis in cultured hepatocytes

The synthesis of $\text{E. coli}$ proteins was examined, by two-dimensional O'Farrell gels, in mutant strains defective in all possible combinations of the RNA processing enzymes RNase III, RNase E and RNase P. We found that the synthesis of most proteins was unaffected; however, the synthesis of a significant number of proteins, 21 out of 80 tested, was drastically reduced in the strain defective in all three enzymes. It appears that the two enzymes RNase III and RNase E are responsible for most of these changes.