[Effect of sodium selenite on RNA synthesis in loach embryos].

The effects of sodium selenite on the ribonucleic acid synthesis in normal diploid embryos and isolated nuclei of the loach Misgurnus fossilis were studied. The relative rate of synthesis was determined from incorporation of [3H]uridine into the total RNA, taking into consideration the incorporation of the label into the total acid-soluble fraction and into phosphorylated derivatives of uridine. It was shown that sodium selenite inhibits the RNA synthesis in loach embryos at the gastrula stage. It was also found that sodium selenite exerts an inhibiting effect on the activity of form I of DNA-dependent RNA-polymerase in isolated loach nuclei without affecting the activity of the enzyme form II.