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STUDIES ON RAPIDLY LABELLED NUCLEAR RNA OF RAT BRAIN
Author(s) -
Oravec M.
Publication year - 1973
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1973.tb06029.x
Subject(s) - rna , ribosomal rna , dna , microbiology and biotechnology , rna polymerase i , biology , labelling , biochemistry , 5s ribosomal rna , ribosome , rna dependent rna polymerase , gene
—Methyl albumin kieselguhr chromatography (MAK) has been employed to separate rat brain nuclear RNA, labelled in vivo with [ 3 H]uridine, into three major fractions. The first fraction (QI RNA) is ribosomal in nature for it has a high G + C/U ratio and is methylated by [methyl‐ 3 H] methionine. The other two fractions (Q2 RNA and TD RNA) are DNA‐like for they exhibit a low G + C/U ratio and are labelled minimally by methionine. Pure ribosomal RNA chromatographs almost entirely in the Q1 RNA fraction. Labelling studies indicate that ribosomal RNA and DNA‐like RNA behave differently. Initially, the label in the DNA‐like RNA fractions increases rapidly and in a linear fashion for the first 30 min, but thereafter decreases rapidly and reaches a steady state level by 1 h and remains so up to at least the 2 h period. In contrast, the labelling of ribosomal RNA is much slower than that of DNA‐like RNA during the first 30 min; however, unlike DNA‐RNA, the labelling of ribosomal RNA still continues to increase linearly thereafter. Thus, during longer labelling periods, ribosomal RNA is labelled more rapidly than DNA‐like RNA. It appears that the labelling of ribosomal RNA relative to DNA‐like RNA is more rapid in liver than in brain.