Isolation and characterization of different-sized nucleoli from Ehrlich ascites tumor cells

Higashi, Ken; Kohno, Masayuki; Nishinaga, Keiji; Hanasaki, Noriko; Shikichi, K.; Takatsuka, Yuichi; Sakamoto, Yukiya

doi:10.1016/0014-4827(75)90454-1

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…It should also be noted that in the active nucleoli of the G2 period a good correlation is observed between the volume of the nucleolus and the number of FCs (Table II; r= 0.99). This conclusion is fully consistent with the results of a biochemical analysis of the number of ribosomal genes in large, medium-sized, and small nucleoli isolated from Ehrlich cells [11].…”

Section: Discussionsupporting

confidence: 90%

Quantitative ultrastructural study of nucleolus‐organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis)

Зацепина

Hozák

Chentsov

1988

Biology of the Cell

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The quantitative characteristics of chromosomal nucleolus-organizing regions (NORs) and some other nucleolar components were studied on ultra-thin sections of pig embryo kidney cells (PK cells). It was shown that: 1) nucleoli-per-cell volumes were 3 times smaller in the G0 period than in the G2 period; 2) the number of fibrillar centers (FCs) per cell in the G0 period, the G2 period, and at metaphase was equal to 7, 33.7, and 8, respectively; 3) mean volumes of individual FCs in the G0 period (0.033 +/- 0.005 micron3), G2 period (0.014 +/- 0.001 micron3), and at metaphase (0.025 +/- 0.002 micron3) were significantly different; 4) the total volumes of FCs calculated per haploid set of chromosomes were practically the same in the G0 (0.105 micron3) and G2 (0.107 micron3) periods, but were twice as large as those at metaphase (0.04-0.05 micron3). These data show that partial activation and inactivation of ribosomal genes in interphase PK cells are not accompanied by a considerable change in the total volume of FCs and may be due to the fragmentation and fusion of individual FCs. Complete inactivation of ribosomal genes in mitosis results in a decrease of total volumes of FCs per cell; 5) in G0 and G2 periods the total volume of the dense fibrillar component per nucleolus is practically proportional to the nucleolus volume (r = 0.99); 6) in the G2 period, the nucleolus volume is also proportional to the number of FCs (r = 0.99; 7) the volume of the dense fibrillar component within individual fibrillar complexes is not a constant one.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionsupporting

confidence: 90%

Quantitative ultrastructural study of nucleolus‐organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis)

Зацепина

Hozák

Chentsov

1988

Biology of the Cell

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“…Nucleoli are the major sites for bot,h biosynthesis of ribosomal precursor RNA and its rnaturation to ribosomes (Busch & Smetana, 1970 (Higashi et al, 1975;Takatsuka et al, 1976), are highly active t.o form ribosomes (Jacob et aL, 1967 (Hirano et al, 1975) and activities of DNA polymerases a and B were detectecl in the nucleoli isolated from mouse tumor cells.…”

Section: Introductionmentioning

confidence: 99%

Contents of DNA Polymerases in Nucleoli and Nucleolar Chromatins of Ehrlich Ascites Tumor Cells

Hirano

Higashi

1981

J UOEH

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DNA polymerases in the nuclei and nucleoli isolated from rapidly growing tumor cells of mice were characterized and their contents were examined, As the distribution of enzymes might be altered depending on the homogenizing medium, to isolate nuclei, two different procedures were employed for examining the intracellular distribution of DNA polymerases: one involved hypotonic buffer containing MgC12 and Nonidet P 40 (hypoLonicmagnesium procedure), and the other isetonic sucrose containing CaCi2 and no detergent(sucrose-calcium procedure).

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“…It is still unknown whether the nucleolar chromatin contains other information besides rDNA. One characteristic of nucleolar DNA in mouse cells is that it contains a large amount of satellite DNA (12,16), but the physiological role of satellite DNA in the nucleoli is still unknown.…”

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confidence: 99%

Ribosomal Genes of Fractionated Chromatin from Nucleoli of Ehrlich Ascites Tumor Cells

Higashi

Hanasaki

Shikichi

et al. 1975

Cell Struct. Funct.

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Chromatin from isolated Ehrlich ascites tumor cell nucleoli was fractionated on a sucrose gradient to examine the distribution of ribosomal genes. The isolated nucleoli were treated with polyvinylsulphate, and then the ribonucleoprotein particles were extracted with 20 mM dithiothreitol in buffer solution. The chromatin was then solubilized by sonication in 10 mM Tris-HCI buffer (pH 8.0). Centrifugation of solubilized chromatin fraction on a sucrose gradient gave two peaks of chromatin containing approximately equal amounts of DNA, regardless of whether the sonication period was 20 sec or 40 sec. Peak I (which sedimented slower) had less RNA than peak II. Ribonucleoprotein particles appeared to merely cosediment with peak II because the profiles of DNA component differed from RNA. Therefore, the presence of ribonucleoprotein particles was probably not the primary cause of the rapid sedimentation of peak II. Examination of the distribution of ribosomal genes in the fractionated nucleolar chromatin by hybridization of DNA with "Plabeled ribosomal RNA showed that peak I contained three times more ribosomal genes than peak II. Fractionation of DNA in the chromatin fractions by CsC1 equilibrium density gradient centrifugation showed that the profiles of DNA complimentary to ribosomal RNA in the two fractions were essentially similar, but that peak I contained more ribosomal genes than peak II.

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Isolation and characterization of different-sized nucleoli from Ehrlich ascites tumor cells

Cited by 6 publications

References 18 publications

Quantitative ultrastructural study of nucleolus‐organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis)

Quantitative ultrastructural study of nucleolus‐organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis)

Contents of DNA Polymerases in Nucleoli and Nucleolar Chromatins of Ehrlich Ascites Tumor Cells

Ribosomal Genes of Fractionated Chromatin from Nucleoli of Ehrlich Ascites Tumor Cells

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