Uridine Nucleotide Incorporation into Pigeon Liver Microsome Ribonucleic Acid

Results of experiments on pigeon liver cytoplasmic fractions are reported that show that desoxyribonucleic acid (RNA) synthesis occurs in the microsome fraction. The conditions required for nucleotide incorporation into pigeon liver microsomal RNA were determined and a comparison made between uridine monophosphate, uridinc diphosphate, and uridine triphosphate (UTP) as RNA precursors using C/sup 14/-labeled nucleotides characterized spectrophotometrically and by chromstography with authentic standards. Radioautograms of the chromatograms were made. The zero time binding of UTP to the various subcellular fractions from pigeon liver and of all three uridine nuclcotides to microsomes was measured and resuits are tabulated. Reaction mechanisms involved are discussed. (C.H.)