Effects of 8-azaguanine on the composition of ribonucleic acids from subcellular fractions

Abstract

When albino mice were dosed intraperitoneally with 8-azaguanine, a substantially higher percentage of the analogue was incorporated into mitochondrial and soluble ribonucleic acid than into microsomal ribonucleic acid. The "pH 5.2 supernatant" ribonucleic acid contained a substantially higher proportion of 8-azaguanine than did the ribonucleic acid in the "pH 5.2 precipitate". A higher proportion of the total soluble ribonucleic acid was found in the pH 5.2 precipitate fraction in livers from treated animals. Treatment with 8-azaguanine caused a decrease of about 30% in the total guanine + 8-azaguanine content of mitochondrial ribonucleic acid, but had no significant effects on the proportions of major bases in the other fractions. Substantial changes occurred in the proportions of certain methylated guanines in liver microsomal ribonucleic acid. Traces of 8-aza-adenine were identified in mitochondria from livers of animals dosed with 8-azaguanine. The ribonucleic acid from subcellular fractions of pea and bean seedlings treated with 8-azaguanine showed a pattern of distribution of the analogue similar to that found for mouse liver.