The Import Pathway of Human and Thermoplasma 20S Proteasomes into HeLa Cell Nuclei Is Different from That of Classical NLS-Bearing Proteins

1999 ◽  
Vol 380 (10) ◽  
Author(s):  
Jutta Mayr ◽  
Huei-Rong Wang ◽  
Petra Nederlof ◽  
Wolfgang Baumeister
Keyword(s):  
Hela Cell ◽  
Cell Nuclei

scholarly journals Polyanion-induced release of polyribosomes from HeLa cell nuclei

1975 ◽  
Vol 250 (23) ◽  
pp. 9198-9205
Author(s):  
JA Goidl ◽  
D Canaani ◽  
M Boublik ◽  
H Weissbach ◽  
H Dickerman
Keyword(s):  
Hela Cell ◽  
Cell Nuclei

Covalent guanylyl intermediate formed by HeLa cell mRNA capping enzyme

1982 ◽  
Vol 2 (8) ◽  
pp. 993-1001
Author(s):  
D Wang ◽  
Y Furuichi ◽  
A J Shatkin
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Hela Cell ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Enzyme Complex ◽  
Cell Nuclei ◽  
Dodecyl Sulfate ◽  
Enzyme Intermediate

Guanylyltransferase, an enzyme that catalyzes formation of mRNA 5'-terminal caps, was isolated from HeLa cell nuclei. The partially purified preparation, after incubation with [alpha-32P]GTP, yielded a single radiolabeled polypeptide by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The guanylylated product was stable at neutral and alkaline pHs and had a pI of 4 by isoelectric focusing. An apparent molecular weight of approximately 68,000 was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. The formation of a covalently linked, radiolabeled GMP-protein complex and the associated release of PPi required the presence of [alpha-32P]GTP and divalent cations and incubation between pH 7 and 9. Reaction with [beta-32P]GTP, [alpha-32P]CTP, [alpha-32P]UTP, or [alpha-32P]ATP did not label the approximately 68,000-dalton polypeptide. Phosphoamide linkage of the GMP-enzyme complex was indicated by its sensitivity to cleavage by acidic hydroxylamine or HCl and not by NaOH or alkaline phosphatase. Both formation of the GMP-enzyme intermediate and synthesis of cap structures of type GpppApG from GTP and ppApG were remarkably temperature independent; the rates of enzyme activity at 0 to 4 degrees C were 30% or more of those obtained at 37 degrees C. Radiolabeled GMP-enzyme complex, isolated by heparin-Sepharose chromatography from reaction mixtures, functioned effectively as a GMP donor for cap synthesis with 5'-diphosphorylated oligo- and polynucleotide acceptors. Alternatively, protein-bound GMP could be transferred to PPi to form GTP. The formation of a guanylylated enzyme intermediate appears to be characteristic of viral and cellular guanylyltransferases that modify eucaryotic mRNA 5' termini.

Three-dimensional approaches to the residual structure of histone-depleted HeLa cell nuclei

1984 ◽  
Vol 87 (2) ◽  
pp. 112-123 ◽  
Author(s):  
Dominique Bouvier ◽  
Jean Hubert ◽  
Annie-Pierre Seve ◽  
Michel Bouteille ◽  
Peter B. Moens
Keyword(s):  
Hela Cell ◽  
Three Dimensional ◽  
Cell Nuclei ◽  
Residual Structure

Immunocytological detection of AAF-DNA adducts in HeLa cell nuclei

1981 ◽  
Vol 14 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Evelyne Sage ◽  
Norman Gabelman ◽  
Frances Mendez ◽  
Robert Bases
Keyword(s):  
Hela Cell ◽  
Dna Adducts ◽  
Cell Nuclei

scholarly journals The loss of rapidly labelled ribonucleic acid from isolated HeLa cell nuclei

1969 ◽  
Vol 112 (1) ◽  
pp. 71-79 ◽  
Author(s):  
J. W. Watts
Keyword(s):  
Hela Cell ◽  
Incubation Medium ◽  
Sedimentation Coefficient ◽  
Cell Nuclei ◽  
Isolated Nuclei ◽  
Bivalent Cations ◽  
Low Concentrations ◽  
Nuclear Rna ◽  
And Diffusion

1. The loss of nucleic acids and protein from isolated HeLa-cell nuclei was studied. During 4hr. incubation at 37° DNA was conserved, but appreciable amounts of RNA and protein were lost. 2. Two classes of nuclear RNA were distinguished: at least 75% of the RNA was lost from the nuclei relatively slowly through degradation to acid-soluble fragments; the rest of the RNA was lost much more rapidly, not only through degradation to acid-soluble fragments but also through diffusion of RNA out of the nuclei into the incubation medium. 3. The RNA that was preferentially lost was the fraction of nuclear RNA that was rapidly labelled when intact HeLa cells were grown in a medium containing radioactive precursors of RNA. 4. The RNA appearing in the incubation medium was apparently partially degraded and had a sedimentation coefficient of about that of transfer RNA. 5. Both the degradation of RNA and the loss of RNA from the nuclei were sensitive to bivalent cations. Low concentrations of Mg2+ and Mn2+ greatly increased the rate of degradation of the rapidly labelled RNA to acid-soluble fragments, and produced a corresponding decrease in the amount of RNA diffusing into the medium. At higher concentrations they suppressed both degradation and diffusion of RNA. The cations Ca2+, Cu2+, Zn2+ and Ni2+ all progressively inhibited both forms of loss of RNA. 6. Salts of univalent cations produced appreciable effects only at ionic strengths of about 0·2, when degradation to acid-soluble fragments was preferentially inhibited. 7. Both ADP and ATP inhibited loss of RNA at about 30mm. 8. It was concluded that the diffusion of rapidly labelled RNA out of the isolated nuclei was not related to the movement of RNA from nucleus to cytoplasm in vivo, but reflected the ease with which the rapidly labelled RNA detached from the chromatin and the permeability of the membranes of isolated nuclei.

Effect of 1-β-D-arabinofuranosylcytosine triphosphate on DNA synthesis in isolated HeLa cell nuclei

Biochemistry ◽  
1976 ◽  
Vol 15 (16) ◽  
pp. 3647-3652 ◽  
Author(s):  
Erik Wist ◽  
Hans Krokan ◽  
Hans Prydz
Keyword(s):  
Hela Cell ◽  
Dna Synthesis ◽  
Cell Nuclei

scholarly journals A novel heterogeneous nuclear RNP protein with a unique distribution on nascent transcripts.

1989 ◽  
Vol 109 (6) ◽  
pp. 2575-2587 ◽  
Author(s):  
S Piñol-Roma ◽  
M S Swanson ◽  
J G Gall ◽  
G Dreyfuss
Keyword(s):  
Hela Cell ◽  
Rna Binding ◽  
Consensus Sequence ◽  
Cdna Clones ◽  
Cell Nuclei ◽  
Intense Staining ◽  
L Protein ◽  
Isolation And Characterization ◽  
Hnrnp Protein ◽  
Nascent Transcripts

Immediately after the initiation of transcription in eukaryotes, nascent RNA polymerase II transcripts are bound by nuclear proteins resulting in the formation of heterogeneous nuclear ribonucleoprotein (hnRNP) complexes. hnRNP complexes from HeLa cell nuclei contain greater than 20 major proteins in the molecular mass range of 34,000-120,000 D. Among these are the previously described A, B, and C groups of proteins (34,000-43,000 D) and several larger, and as yet uncharacterized, proteins. Here we describe the isolation and characterization of a novel hnRNP protein termed the L protein (64-68 kD by mobility in SDS-polyacrylamide gels). Although L is a bona fide component of hnRNP complexes, it also appears to be a different type of hnRNP protein from those previously characterized. A considerable amount of L is found outside hnRNP complexes, and monoclonal antibodies to the L protein also strongly stain unidentified discrete nonnucleolar structures, in addition to nucleoplasm, in HeLa cell nuclei. Interestingly, the same antibodies stain the majority of nonnucleolar nascent transcripts from the loops of lampbrush chromosomes in the newt, but the most intense staining is localized to the landmark giant loops. The L protein is the first protein of giant loops identified so far, and antibodies to it thus provide a useful tool with which to study these unique RNAs. In addition, isolation and sequencing of cDNA clones for the L protein from human cells predicts a glycine- and proline-rich protein of 60,187 D, which contains two 80 amino acid segments only distantly related to the RNP consensus sequence-type RNA-binding domain. The L protein, therefore, is a new type of hnRNP protein.

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