Size Distribution of Rat Liver Nuclear RNA Containing mRNA Sequences (original) (raw)
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Journal of Molecular Biology, 1977
Methods were developed for the isolation and use of large quantities of unique DNA sequences complementary to polysomal polyadenylated messenger RNA (poly(A) +mRNA). The complementary DNA was prepared by annealing poly-(A)+mRNA to total non-repetitive genomic DNA and subsequent purification of the DNA-RIqA hybrids away from the bulk of the DNA. The mDNA:~ was tested for specificity in a series of DNA excess hybridization reactions involving mRNA and various subfractions of heterogeneous nuclear RNA. The results suggest that the mDNA is not grossly contaminated with non-mRNA sequences and thus the method may be used to obtain mDNA for use in experiments where mDNA excess hybridizations are required.
Nucleic Acids Research, 1980
Polysomal and nuclear poly(A)-containing RNA of normal rat liver and Novikoff hepatoma cells have been compared by cDNA.RNA hybridization kinetics. Homologous hybridization reactions revealed a total kinetic complexity of about 1.6x101 and 1.38x 1010 daltons for liver and Novikoff mRNA respectively. The high abundance component present in liver cannot be detected in Novikoff. It was found from heterologous reactions that about 30% by weight of mRNA sequences are specific to liver. Determination of the nuclear poly(A)-containing RNA complexities revealed that about 5.5% and 4% of the haploid genome is expressed in the liver and Novikoff respectively. In a heterologous reaction, up to 30% of the liver cDNA failed to form hybrids with Novikoff nuclear RNA. Cross hybridizations have further revealed abundance shifts in both nuclear and polysomal RNA populations. Some sequences abundant in liver are less abundant in Novikoff and some rare liver sequences are relatively abundant in Novikoff.
Proceedings of the …, 1977
The effects of UV irradiation on the incorporation of [3H1uridine in HeLa (human) cell mRNA, rRNA, heterogeneous nuclear RNA (hnRNA) and early mRNA from adenovirus type 2 have been compared. The UV target size of cell mRNA is at least 3 times larger than the average size of the mRNA itself and larger than the adenovirus-2 early mRNA, which is known to derive from transcription units of about 1.5-5.0 kilobases. The UV target size of hnRNA, in contrast, is about the same as its size determined by sedimentation and overlaps with the target size of mRNA. It is concluded that most mRNA derives from a higher molecular weight hnRNA molecule.
European Journal of Biochemistry, 1979
The mRNA species which exist in the HeLa cell polyribosomes in a form devoid of A sequences longer than 8 nucleotides constitute the poly(A)-free class of mRNA. The rapidly labelled component of this mRNA class shares no measurable sequence homology with poly(A)-containing RNA. If poly(A)-free mRNA larger than 12 S labelled for 2 h in vivo is hybridized with total cellular DNA, it hybridizes primarily with single-copy DNA. When a large excess of steady poly(A)-containing RNA is added before hybridization of labelled poly(A)-free RNA, no inhibition of hybridization occurs. This indicates the existence of a class of poly(A)-free mRNA with no poly(A)containing counterpart. Some mRNA species can exist solely as poly(A)-containing mRNAs. These mRNAs in HeLa cells are found almost exclusively in the mRNA species present only a few times per cell (scarce sequences). Some mRNA species can exist in two forms, poly(A)containing and lacking, as evidenced by the translation data in vitvo of Kaufmann et al. [Pvoc. Nut1 Acud. Sci. U.S.A. 74, 4801-4805 (1977)l. In addition, if cDNA to total poly(A)-containing mRNA is fractionated into abundant and scarce classes, 47 7; of the scarce class cDNA can be readily hybridized with poly(A)-free mRNA.
Metabolic heterogeneity of nuclear poly (A)-containing RNA in mouse liver
Nucleic Acids Research, 1977
The analysis by the approaSh to equilibrium labeling method has shown that the poly(A) fraction of liver hnRNA is not a uniform class of molecules, but is comprised of two distinct subclasses with half-lives of 5 and 60 min, while the poly(A) hnRNA was metabolically homogeneous and turned over with a rather uniform half-life of 30 min. The results suggest that (a) poly(A) synthesis and addition is not limiting for the rate of hnRNA processing, and (b) there is a correlation between the kinetics of mRNA appearance in the cytoplasm and kinetic behavior of their possible nuclear precursors.
simplex virus type 1. cells infected with herpes high-molecular-weight RNA in Nuclear processing of viral http://jvi.asm.org/content/35/2/382 at: Updated information and services can be found These include: CONTENT ALERTS more» (when new articles cite this article), Receive: RSS Feeds, eTOCs, free email alerts http://journals.asm.org/site/misc/reprints.xhtml Information about commercial reprint orders: http://journals.asm.org/site/subscriptions/ To subscribe to to another ASM Journal go to:
The Journal of cell biology, 1980
To explore the relationships between transcription, messenger RNA (mRNA) processing, and nuclear structure, ribonucleoprotein particles containing heterogeneous nuclear RNA (hnRNP) have been purified from globin-producing mouse Friend erythroleukemia cells. These nuclear hnRNP particles sediment at 50S-200S and contain, in addition to high molecular weight hnRNA, a specific set of nuclear proteins predominated by a major component of approximately 38,000 mol wt. The hnRNP particles are free of histones and ribosomal structural proteins, indicating their purification from the two other major nucleoprotein components of the nucleus: chromatin and nucleolar ribosomal precursor RNP particles. Th authenticity of the Friend cell hnRNP particles is demonstrated by the results of reconstruction experiments with deproteinized hnRNA, and by the resistance of the articles to dissociation during isopycnic banding in Cs2SO4 gradients without prior aldehyde fixation. Hybridization analysis with c...
European Journal of Biochemistry, 1979
Poly(A)-containing messenger RNA was isolated from polysomes of Ehrlich ascites tumor cells, and analyzed for sequence complexity by hybridization to its complementary DNA. The results indicate the presence of about 27000 diverse mRNA species in mouse Ehrlich ascites tumor cells. Total nuclear RNA was also hybridized to cDNA transcribed from ,polysomal poly(A)-containing mRNA up to an rot of 3000 M . s. It was found that all classes of the polysomal poly(A)-containing mRNA sequences were also present in the nucleus, although the distribution varied. About 2 % of the total nuclear RNA sequences were expressed as total polysomal poly(A)-containing mRNA. We also report that the total percentage of the haploid mouse genome transcribed in Ehrlich cells is significantly higher than that found in other mouse cells previously examined for poly(A)containing mRNA sequence complexity.