SEPARATION AND CHARACTERIZATION OF THE MAIN METHYLATED NUCLEOBASES FROM NUCLEAR, CYTOPLASMIC AND POLY (A)(-PERFORMANCE LIQUID-CHROMATOGRAPHY AND MASS-SPECTROMETRY() RNA BY HIGH)

We were able to detect nine methylated nucleobases (3-methyluracil, 1- , 2-, 3- and 7-methylguanine, 1-, 2-, 3-and 6-methyladenine) in RNA fr om rat and calf liver, baker's yeast, Torula and Euglena cells by usin g reversed-phase high-performance liquid chromatography and thermospra y mass spectrometry. Total cellular, nuclear, cytoplasmic and poly (A) (+) RNA from rat liver showed marked methylation, mainly of 1- and 3-m ethylguanine, and 3- and 2-methyladenine. These bases were especially abundant in nuclear RNA and, to a lesser extent, in poly (A)(+) RNA. I n contrast, 7-methylguanine and 6-methyladenine were poorly represente d in poly (A)(+) RNA.