Distribution of Low-Molecular-Weight RNAs in Avian Erythroblast Nuclear Ribonucleoprotein Complexes Associated with Pre-messenger RNA (original) (raw)

Duck erythroblast nuclei, isolated under conditions designed to preserve lysosome integrity, were extracted to yield a bulk population of nuclear ribonucleoprotein (nRNP) particles which, when fractionated on sucrose gradients, was resolved into two classes of RNA-protein complexes containing low-molecular-weight RNA. The classical pre-messenger ribonucleoprotein complex (pre-mRNP), which had been previously characterized in this laboratory and was shown to contain rapidly-labeled pre-messenger RNA (pre-mRNA) sequences, was observed to contain approximately eight discrete species of nuclear RNA between 90 and 230 nucleotides in length (major species of M, 80000 and 55000, and minor species of M , 61 000, 58000, 51000, 38000, 36000 and 32000). The size and relative distribution of these RNA sequences indicated that they were the small nuclear RNA species previously described in the literature.