scholarly journals Distribution of newly formed ribosomal proteins in HeLa cell fractions.

1979 ◽  
Vol 80 (3) ◽  
pp. 767-772 ◽  
Author(s):  
J R Warner
Keyword(s):  
Hela Cell ◽  
Hela Cells ◽  
Ribosomal Proteins ◽  
Actinomycin D ◽  
Precursor Rna ◽  
Cell Fractions ◽  
Ribosomal Precursor

The distribution of newly formed ribosomal proteins between cytoplasmic, nucleoplasmic, and nucleolar fractions of HeLa cells was determined. All but a few of the newly formed ribosomal proteins were concentrated 10- to 50-fold in the nucleolus and two- to fivefold in the nucleoplasm. Nevertheless, substantial amounts were found in the cytoplasm. Pretreatment of cells with actinomycin D to deplete the nucleolar pool of ribosomal precursor RNA had no effect on the concentration of newly formed ribosomal proteins in the nucleus, but did lead to an increased amount in the nucleoplasm at the expense of the nucleolus.

Regulation of ribosome synthesis during compensatory renal hypertrophy in mice

1987 ◽  
Vol 253 (4) ◽  
pp. C506-C513 ◽  
Author(s):  
A. J. Ouellette ◽  
R. Moonka ◽  
A. D. Zelenetz ◽  
R. A. Malt
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Rdna Transcription ◽  
Renal Hypertrophy ◽  
Renal Growth ◽  
Compensatory Renal Hypertrophy ◽  
Steady State Levels ◽  
Precursor Rna ◽  
Ribosomal Precursor

Ribosomal synthesis was studied at the transcriptional and translational levels to investigate the mechanisms of ribosome accretion during compensatory renal hypertrophy. As measured by in vitro transcriptional runoff comparisons 6-48 h after surgery, nuclei from the kidney remaining after contralateral nephrectomy show an increase of up to 150% in the rate of synthesis of ribosomal precursor RNA. The rate of rDNA transcription is 40-50% greater than control values as early as 6 h after nephrectomy; by 48 h, the rate returns to normal. In contrast to the stimulated transcription of rDNA and accretion of rRNA, the steady-state levels and the cytoplasmic distribution of ribosomal protein mRNAs S16 and L10 remain unchanged during induced renal growth. Thus coordinate production of adequate protein for increased assembly of ribosomes during induced renal growth appears to be accomplished by increasingly efficient translation of existing ribosomal protein mRNAs or by post-translational stabilization of ribosomal proteins. The rate of rDNA transcription may be regulated by accelerating the transcription of already functioning genes or, more likely, by recruiting transcription units that are transcriptionally inactive in the normal kidney.

scholarly journals EFFECT OF TEMPERATURE OF ALDEHYDE FIXATION ON THE RADIOAUTOGRAPHIC LOCALIZATION OF RIBONUCLEOPROTEIN IN NUCLEOLI OF HELA CELLS

1967 ◽  
Vol 34 (3) ◽  
pp. 721-734 ◽  
Author(s):  
R. Gerald Suskind
Keyword(s):  
Hela Cells ◽  
Nucleolar Protein ◽  
Effect Of Temperature ◽  
Aldehyde Fixation ◽  
Ionic Dissociation ◽  
Protein Label ◽  
Precursor Rna ◽  
A Site ◽  
Ribosomal Precursor

In efforts to clarify the role of the nucleolus and substructures thereof in the assembly or synthesis of protein associated with formation of the complete ribosome, the effect of variation of some conditions of aldehyde fixation on the intranuclear distribution of lysine-3H, arginine-3H, and uridine-3H was studied by differential grain count in radioautographs of PPLO-free HeLa cells. It was found that the nucleolus is a site of rapid assembly or synthesis of a protein, the synthesis of which is inhibited equally by puromycin (200 µg/ml) and by actinomycin D under conditions inhibitory for ribosomal precursor RNA synthesis (P < 0.01). This protein is fixed by phosphate-buffered formalin or glutaraldehyde at pH 7.3, but the label is diminished by fixation in customarily employed acetic ethanol or in formalin at acid pH. Elevation of temperature of formalin or glutaraldehyde fixatives to 37°C consistently reduces the nucleolar protein label, but not the RNA label, by a proportion identical with that incurred by puromycin or actinomycin inhibition. This proportional reduction of nucleolar protein label occurs without evident loss of total grain count and is independent of length of fixation between 30 min and 4 hr, but it is not observed at 23°C. The data support the interpretation that the proportion of nucleolar protein not fixed at 37°C is associated with nucleolar ribosomal RNA but that it is dissociated at 37°C in formalin or glutaraldehyde fixatives, probably on the basis of ionic dissociation of a conjugated ribonucleoprotein.

scholarly journals Action of dichlorobenzimidazole riboside on RNA synthesis in L-929 and HeLa cells.

1976 ◽  
Vol 69 (2) ◽  
pp. 229-240 ◽  
Author(s):  
I Tamm ◽  
R Hand ◽  
L A Caliguiri
Keyword(s):  
Hela Cells ◽  
Rna Synthesis ◽  
Dose Range ◽  
Inhibitory Effect ◽  
Mouse Fibroblast ◽  
L Cells ◽  
Uridine Uptake ◽  
High Concentrations ◽  
Precursor Rna ◽  
Ribosomal Precursor

5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) inhibits RNA synthesis in L-929 cells (mouse fibroblast line) and HeLa cells (human epitheloid carcinoma line) within 2 min of addition of the compound to the medium. By removing DRB from the medium, the inhibition is promptly and completely reversed after treatment of cells for as long as 1 h or even longer. The inhibitory effect of DRB on the overall rate of RNA synthesis is similar in L and HeLa cells and is markedly concentration-dependent in the low dose range (5-20 muM or 1.6-6.4 mug/ml), but not as higher concentrations of DRB. At a concentration of 12 muM, DRB has a highly selective inhibitory effect on the synthesis of nuclear heterogenous RNA in L cells. At higher concentrations, there is also inhibition of 45 S ribosomal precursor RNA synthesis, but at all concentrations the effect on heterogeneous RNA synthesis in L cells in considerably greater than that on preribosomal RNA synthesis. In HeLa cells, too, DRB has a selective effect on heterogeneous RNA synthesis, but quantitatively the selectivity of action is somewhat less pronounced. In both L and HeLa cells, the inhibition of synthesis of nuclear heterogeneous RNA is incomplete even at very high concentrations of DRB (150 muM). Thus, while DRB is a selective inhibitor of nuclear heterogeneous RNA synthesis, not all such RNA synthesis is sensitive to inhibition. It is proposed that messenger precursor RNA synthesis may largely be sensitive to inhibition by DRB. In short-term experiments, DRB has no effect on protein synthesis in L or HeLa cells. DRB has a slight to moderate inhibitory effect on uridine uptake into L cells and a moderate to marked effect on uptake of uridine into HeLa cells.

scholarly journals Relative stoichiometry in ribosomal proteins in HeLa cell nucleoli.

1976 ◽  
Vol 251 (10) ◽  
pp. 2876-2881 ◽  
Author(s):  
W F Phillips ◽  
E H McConkey
Keyword(s):  
Hela Cell ◽  
Ribosomal Proteins

Interaction of Candida albicans with genital mucosa: effect of sex hormones on adherence of yeasts in vitro

1988 ◽  
Vol 34 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Aliza Kalo ◽  
Esther Segal
Keyword(s):  
Candida Albicans ◽  
Hela Cell ◽  
Sex Hormones ◽  
Hela Cells ◽  
Cell Types ◽  
Vaginal Candidiasis ◽  
Genital Mucosa ◽  
Hela Cell Lines ◽  
I Cells

Findings from our previous studies revealed a correlation between the level of adherence in vitro of Candida albicans to human exfoliated vaginal epithelial cells (VEC) and the hormonal status of the cell donors. In the present study we investigated the effect of the sex hormones estradiol, estriol, progesterone, and testosterone on the binding of the yeasts to HeLa cell lines and VEC in vitro. Monolayers of HeLa cells were exposed to the hormones and yeasts under controlled conditions. The number of adherent yeasts per square millimetre of HeLa cell monolayers and the percentage of VEC with adherent yeasts was estimated by microscopic counts. The results showed that the tested sex hormones affected at various degrees the adhesion of yeasts to HeLa cells or VEC. Progesterone had the most marked effect, leading to a significant increase in the number of adherent yeasts to HeLa cells or in the percentage of adhesion of VEC. In addition, VEC were separated on Percoll gradients into the two cell types: superficial (S) and intermediate (I), cell types which appear physiologically under increased serum levels of estradiol or progesterone, respectively. Adhesion assays with the separated cell populations revealed an increased binding capacity of the I cells. The finding that progesterone increased the adherence of yeasts to genital mucosa and that VEC of the I type have a higher capacity to adhere the yeasts is compatible with our previous observation that increased numbers of I cells, appearing under high level of progesterone, are found in situations known to have predisposition to vaginal candidiasis. Thus, our data point to a possible involvement of the hormone progesterone in the adherence of C. albicans to genital epithelium.

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