Detection of mRNA sequences in nuclear 30S ribonucleoprotein subcomplexes (original) (raw)
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Biochemical Journal, 2000
Pre-mRNA processing in eukaryotes is thought to take place on a multitude of nuclear ribonucleoprotein (RNP) complexes, the most abundant of them being the heterogeneous nuclear (hn) RNP complexes. The identification in mammalian nuclear extracts of a novel, less-abundant 70-110 S heterogeneous RNP, named large heterogeneous nuclear RNP (LH-nRNP), has previously been reported by Aidinis, Sekeris and Guialis (1995) Nucleic Acids Res. 23, 2742-2753. The structural composition of the LH-nRNP complex has been determined following the production of polyclonal antibodies against the major protein constituents of the complex, the pair of the 72\74-kDa polypeptides. In the present study evidence is shown to prove that the 72\74-kDa proteins are members of the hnRNP M protein family, hereafter referred to as 72\74(M) polypeptides. The extensive application of two-dimensional gel electrophoresis, combined with specific immunoprecipitation and immuno-
Biochimica et biophysica acta, 1979
70-130 S polyparticles as well as 38 S monoparticles were isolated from rat liver nuclei and analyzed in respect to their RNA components by microgel polyacrylamide electrophoresis in formamide. In addition to the high molecular weight polydisperse hnRNA of polyparticles several low molecular weight RNAs (snRNA) were detected. There are at least six distinct snRNA species in polyparticles. Except for one species, which is missing, 38 S monoparticles showed a similar snRNA pattern. From densitometer tracings of microgels the snRNAs were estimated to represent about 11% of the total polyparticle RNA. The number of nucleotides for the various snRNAs were determined from a plot of relative electrophoretic mobility versus log number of nucleotides. The possibility that the snRNAs are degradation products of the hnRNA was excluded on the basis of the following findings. (1) The snRNA pattern was similar in mono- and polyparticles. (2) Whereas the hnRNA of polyparticles incubated at 37 degr...
Nuclear Ribonucleoprotein Complexes Containing Polyadenylate from Mouse Ascites Cells
Proceedings of the National Academy of Sciences, 1974
Nuclear poly(A)-containing RNA of mouse ascites cells can be extracted in the form of 15-17 S ribonucleoprotein complexes under conditions in which the bulk of the heterogeneous nuclear RNA is released as 30S complexes. The poly(A)-containing fraction of nuclear extracts has been resolved into two distinct components, 15 and 17 S; neither contains the two polypeptides of 30S ribonucleoprotein. The 17 S particle contains approximately six polypeptide species of molecular masses 17,000-30,000 daltons. The 15S complex has four distinct polypeptides of higher molecular mass, including a prominent 80,000dalton species.
Small nuclear RNA transcription and ribonucleoprotein assembly in early Xenopus development
The Journal of Cell Biology
The Xenopus egg and embryo, throughout the transcriptionally inactive early cleavage period, were found to contain a store of approximately 8 x 108 molecules of the small nuclear RNA (snRNA) U 1, sufficient for 4,000-8,000 nuclei. In addition, when transcription is activated at the twelfth cleavage (4,000 cell-stage), the snRNAs U1, U2, U4, U5, and U6 are major RNA polymerase II products. From the twelfth cleavage to gastrulation, U1 RNA increases sevenfold in 4 h, paralleling a similar increase in nuclear number. This level of snRNA transcription is much greater than that typical of somatic cells, implying a higher rate of U1 transcription or a greater number of U1 genes active in the embryo. The Xenopus egg also contains snRNP proteins, since it has the capacity to package exogenously added snRNA into immunoprecipitable snRNP particles, which resemble endogenous particles in both sedimentation coefficient and T1 RNase digestibility. SnRNP proteins may recognize conserved secondary structure of U1 snRNA since efficient packaging of both mouse and Drosophila U1 RNAs, differing 30% in sequence, occurs. The Xenopus egg and embryo can be used to pose a number of interesting questions about the transcription, assembly, and function of snRNA.
European Journal of Biochemistry, 1981
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.