Isolation and characterization of ribonucleic acid from cerebral cortex of rat.

Ribonucleic acid isolated from cerebral cortex of mature male and female rats was fractionated by chromatography on methylated albumin Kieselguhr columns or by sucrose gradient centrifugation. Three principal fractions were obtained with analytical ultracentrifuge s~o,~ values of 4, 17, and 28. By comparison with ribonucleic acid prepared from purified rat brain ribosomes, the 17 S and 28 S fractions were shown to be predominantly ribosomal ribonucleic acid. Differences in base analyses between the three fractions were small but significant. Compositions of all fractions were markedly complementary with G = C and A = U.