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Dimario PJ. Cell and Molecular Biology of Nucleolar Assembly and Disassembly. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 239:99-178. [PMID: 15464853 DOI: 10.1016/s0074-7696(04)39003-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nucleoli disassemble in prophase of the metazoan mitotic cycle, and they begin their reassembly (nucleologenesis) in late anaphase?early telophase. Nucleolar disassembly and reassembly were obvious to the early cytologists of the eighteenth and nineteenth centuries, and although this has lead to a plethora of literature describing these events, our understanding of the molecular mechanisms regulating nucleolar assembly and disassembly has expanded immensely just within the last 10-15 years. We briefly survey the findings of nineteenth-century cytologists on nucleolar assembly and disassembly, followed by the work of Heitz and McClintock on nucleolar organizers. A primer review of nucleolar structure and functions precedes detailed descriptions of modern molecular and microscopic studies of nucleolar assembly and disassembly. Nucleologenesis is concurrent with the reinitiation of rDNA transcription in telophase. The perichromosomal sheath, prenucleolar bodies, and nucleolar-derived foci serve as repositories for nucleolar processing components used in the previous interphase. Disassembly of the perichromosomal sheath along with the dynamic movements and compositional changes of the prenucleolar bodies and nucleolus-derived foci coincide with reactivation of rDNA synthesis within the chromosomal nucleolar organizers during telophase. Nucleologenesis is considered in various model organisms to provide breadth to our understanding. Nucleolar disassembly occurs at the onset of mitosis primarily as a result of the mitosis-specific phosphorylation of Pol I transcription factors and processing components. Although we have learned much regarding nucleolar assembly and disassembly, many questions still remain, and these questions are as vibrant for us today as early questions were for nineteenth- and early twentieth-century cytologists.
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Affiliation(s)
- Patrick J Dimario
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803-1715, USA
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Yokoyama Y, Niwa K, Tamaya T. Scattering of the silver-stained proteins of nucleolar organizer regions in Ishikawa cells by actinomycin D. Exp Cell Res 1992; 202:77-86. [PMID: 1380922 DOI: 10.1016/0014-4827(92)90406-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Scattering of the silver-stained proteins of nucleolar organizer regions (Ag-NOR proteins) was produced by actinomycin D in Ishikawa cells. Scattering of Ag-NOR proteins was found only in cells treated with actinomycin D and various other agents had no effect. Scattering was dose-dependent up to 10(-2) micrograms/ml of actinomycin D, but it was not found at higher concentrations that caused marked inhibition of total DNA and RNA synthesis. Actinomycin D (10(-2) micrograms/ml) caused the following changes: (i) nucleolar segregation and (ii) emergence of dense fibrillar bodies in the nucleoplasm. Ag-NOR proteins were observed on the fibrillar centers and surrounding fibrillar components in control nucleoli, on the fibrillar and amorphous zones in segregated nucleoli, and on the dense fibrillar bodies emerging in the nucleoplasm. The scattering of Ag-NOR proteins was due to the argyrophilic nature of the dense fibrillar bodies. Actinomycin D (10(-1) micrograms/ml) also caused similar morphological alterations in the nucleolus and nucleoplasm, but Ag-NOR proteins were observed only on nucleolar remnants.
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Affiliation(s)
- Y Yokoyama
- Department of Obstetrics and Gynecology, Gifu University School of Medicine, Japan
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Abstract
In order to gain further insights into the fundamental structure of the nucleolus, nucleolar remnants of Xenopus and chickens were examined for the presence of fibrillarin and nucleolus organizer region (NOR) silver staining. Nucleolar remnants of Xenopus nucleated red blood cells were found to contain easily detectable amounts of fibrillarin and NOR silver staining. Upon examination of various tissues, fibrillarin and NOR silver staining were detected in nucleoli of Xenopus liver hepatocytes and within nucleoli of oocytes and follicle cells from ovaries of mature female toads. By comparison, nucleolar remnants of adult chicken nucleated red blood cells contained only trace amounts of fibrillarin and NOR silver staining, whereas red blood cell nucleolar remnants of immature chicks had easily detectable amounts of fibrillarin and NOR silver staining. Nucleoli from hepatocytes of both adult and immature chickens demonstrated comparable levels of fibrillarin and NOR silver staining. Since fibrillarin was found in nucleolar remnant structures, we tested for (and detected) its presence in residual nucleoli of in situ nuclear matrix derived from HeLa cells. These findings are discussed in terms of the basic structural and functional organization of the nucleolus.
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Affiliation(s)
- R L Ochs
- W.M. Keck Autoimmune Disease Center, La Jolla, California 92037
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Raska I, Andrade LE, Ochs RL, Chan EK, Chang CM, Roos G, Tan EM. Immunological and ultrastructural studies of the nuclear coiled body with autoimmune antibodies. Exp Cell Res 1991; 195:27-37. [PMID: 2055273 DOI: 10.1016/0014-4827(91)90496-h] [Citation(s) in RCA: 258] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Studies with human autoimmune sera identified auto-antibodies reacting with a novel antigen of 80 kDa. In interphase mammalian cells, the 80-kDa antigen was enriched in nuclear coiled bodies and was used as a marker for this nuclear structure. This antigen was subsequently named p80-coilin. By light and electron microscopic immunocytochemistry, a number of other antigens were also localized to the coiled body, including components of small nuclear ribonucleoproteins which are involved in the processing of nucleolar and extranucleolar RNA. Although the function of the coiled body is unknown, the presence of these subcellular particles might indicate an involvement in RNA metabolism. The identification of a protein highly enriched in this structure and the availability of specific antibodies might help in its isolation and the study of its function.
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Affiliation(s)
- I Raska
- W. M. Keck Autoimmune Disease Center, Scripps Clinic and Research Foundation, La Jolla, California 92037
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Raska I, Ochs RL, Salamin-Michel L. Immunocytochemistry of the cell nucleus. ELECTRON MICROSCOPY REVIEWS 1990; 3:301-53. [PMID: 2103346 DOI: 10.1016/0892-0354(90)90006-e] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This electron microscopic review addresses in situ immunocytochemistry of the mammalian cell nucleus with special reference to the use of autoantibodies, which are the major source of antinuclear antibodies. The localization of many key nuclear antigens is documented and immunocytochemical data are related to the major functional processes of transcription and processing of RNA and to replication of DNA.
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Affiliation(s)
- I Raska
- W. M. Keck Autoimmune Disease Center, Scripps Clinic and Research Foundation, La Jolla, CA 92037
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Yamazaki Y, Okada M. Differences in Fine Structures between Normal and RNA-induced Drosophila Pole Cells. (Drosophila pole cell/fine structure/polar granule/nuclear body/cytoplasmic determinant). Dev Growth Differ 1989. [DOI: 10.1111/j.1440-169x.1989.00549.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hu YH, Liang H, Jiang YQ. Study on mechanism of micronucleoli formation by laser microirradiation. CELL BIOPHYSICS 1989; 14:257-69. [PMID: 2472212 DOI: 10.1007/bf02797272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the male rat kangaroo cell line PTK2, argon laser (514.5 nm) microirradiation of both nucleoli in interphase cells 30, 23, and 12 h before mitosis, and nucleoli in early prophase cells resulted in the formation of micronucleoli, i.e., several small nucleolus-like bodies, in daughter cells. The irradiated cells were stained with methylene blue, which indicated that the nucleolar RNA was destroyed by laser microirradiation. Feulgen staining was applied to the irradiated cells in combination with the measurements of an MPV-II model microphotometer. Irradiated nucleoli were negative for DNA-Feulgen stain, which indicated that nucleolar DNA was destroyed by laser irradiation, so the nucleolar organizer gene was destroyed. After the nucleoli had been irradiated, the cells were continuously incubated at 37 degrees C for 12 and/or 24 h, then fixed and stained with AgNO3. Most of the nucleoli irradiated silver-stained negative that demonstrated that when the nucleoli were irradiated, rDNA was destroyed and transcription stopped. However, some silver grains were found in the nucleoplasm, whereas the nucleoli were silver-stained negative. The results suggest that subsidiary nucleolar organizer loci might exist scattered throughout the genome.
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Affiliation(s)
- Y H Hu
- Institute of Genetics, Academia Sinica, Beijing, China
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Géraud G, Laquerrière F, Masson C, Arnoult J, Labidi B, Hernandez-Verdun D. Three-dimensional organization of micronuclei induced by colchicine in PtK1 cells. Exp Cell Res 1989; 181:27-39. [PMID: 2917606 DOI: 10.1016/0014-4827(89)90179-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In PtK1 cells micronucleated by colchicine, we previously demonstrated that some micronuclei contain a single chromosome. Here, we investigated interphase chromosome organization in micronucleated PtK1 cells using conventional electron microscopy and three-dimensional computer reconstruction. The distribution of micronuclei was not always polarized, but in some cells they formed a ring. When this occurred, centrioles and Golgi apparatus were located inside the ring. On freeze-fracture replicas, we observed that nuclear pore distribution among the micronuclei was heterogeneous, and on thin sections some micronuclei displayed an incomplete nuclear envelope, with gaps in the double membrane and areas without lamina or condensed chromatin. By autoradiography, we showed that the fibrillar dots were not sites of active transcription. We applied three-dimensional reconstruction to one micronucleated cell containing 22 micronuclei whose size indicated that each micronucleus probably contained one chromosome. In this cell we demonstrated that only the smallest micronuclei had an incomplete nuclear envelope. The presence in micronuclei of either nucleoli or fibrillar dots was found to be mutually exclusive. These dots might constitute stores of nucleolar proteins which migrate into micronuclei possessing no ribosomal genes. In NOR-bearing micronuclei, the structural organization was similar to that of diploid nuclei: the nucleoli were attached to the nuclear membrane and a nucleolar canal was seen, even in single-chromosome spherical micronuclei. Taken together, these findings indicate that in the diploid nuclei of PtK1 cells, the three-dimensional organization of the nucleolar domain seems to be directly controlled by the X-chromosome.
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Affiliation(s)
- G Géraud
- Laboratoire de Pathologie Cellulaire, Université Pierre et Marie Curie, Paris, France
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Benavente R, Schmidt-Zachmann MS, Hügle-Dörr B, Reimer G, Rose KM, Scheer U. Identification and definition of nucleolus-related fibrillar bodies in micronucleated cells. Exp Cell Res 1988; 178:518-23. [PMID: 3049124 DOI: 10.1016/0014-4827(88)90420-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Small nucleolus-related bodies which occur in the nucleoplasm of "micronuclei" lacking nucleolar organizers have been studied by immunofluorescence microscopy. These bodies stained specifically with three different antibodies directed against proteins that are normally associated with the dense fibrillar component of functional nucleoli, but not with antibodies specific for certain proteins of the granular component or the fibrillar centers. Our data show that, in the absence of rRNA genes, the various constituent proteins characteristic of the dense fibrillar component spontaneously assemble into spherical entities but that the subsequent fusion of these bodies into larger structures is prevented in these micronuclei. The similarity between these nucleolus-related bodies of micronuclei and the prenucleolar bodies characteristic of early stages of nucleologenesis during mitotic telophase is discussed.
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Affiliation(s)
- R Benavente
- Institute of Zoology I, University of Würzburg, Federal Republic of Germany
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Sato S. Cytological evidence on the ability of the nucleolus organizing regions to assemble pre-existing nucleolar material. EXPERIENTIA 1988; 44:264-6. [PMID: 2450777 DOI: 10.1007/bf01941733] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The treatment of Vicia faba root tips with 5-azacytidine caused unequal allotment of the chromosomes; after one cell cycle, a pair of daughter nuclei was produced, one of which carried the nucleolus organizing regions (NORs) and the other of which lacked them. The pre-existing nucleolar material brought into the NOR-carrying daughter nucleus by the chromosomes disappeared concurrently with the appearance of the new nucleoli, whereas in another daughter nucleus without the NOR a number of small nucleolus-like bodies became visible at random positions. These findings suggest that in addition to ribosomal RNA synthesis the NOR has another role in cells; to stimulate the pre-existing nucleolar material to assemble at the NOR itself.
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Affiliation(s)
- S Sato
- Department of Biology, Faculty of Science, Ehime University, Japan
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Ochs RL, Lischwe MA, Shen E, Carroll RE, Busch H. Nucleologenesis: composition and fate of prenucleolar bodies. Chromosoma 1985; 92:330-6. [PMID: 3902398 DOI: 10.1007/bf00327463] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A time course study was conducted on nucleologenesis after release from a mitotic block in the presence and absence of actinomycin D to determine the composition and fate of prenucleolar bodies (PNBs). Prenucleolar bodies, whether naturally occurring or induced by actinomycin D treatment, stain with silver and contain phosphoproteins B23 and C23, two of the major proteins of the interphase nucleolus as determined by double label immunofluorescence with specific antibodies. The nucleolus is formed by fusion of PNBs, which subsequently "reorganize" and form internal fibrillar and peripheral granular regions. Actinomycin D prevents fusion of PNBs, which are then randomly dispersed throughout the nucleus but they still contain proteins B23 and C23. These results demonstrate that the nucleolus is formed by fusion of prenucleolar structures whose biochemical composition resembles the mature nucleolus, since PNBs contain at least two of the major nucleolar proteins.
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Krohne G, Stick R, Kleinschmidt JA, Moll R, Franke WW, Hausen P. Immunological localization of a major karyoskeletal protein in nucleoli of oocytes and somatic cells of Xenopus laevis. J Cell Biol 1982; 94:749-54. [PMID: 6752154 PMCID: PMC2112216 DOI: 10.1083/jcb.94.3.749] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Oocyte nuclei of Xenopus laevis contain two major karyoskeletal proteins characterized by their resistance to extractions in high salt buffers and the detergent Triton X-100, i.e. a polypeptide of 68,000 mol wt which is located in the core complex-lamina structure and a polypeptide of 145,000 mol wt enriched in nucleolar fractions. Both proteins are also different by tryptic peptide maps and immunological determinants. Mouse antibodies were raised against insoluble karyoskeletal proteins from Xenopus oocytes and analyzed by immunoblotting procedures. Affinity purified antibodies were prepared using antigens bound to nitrocellulose paper. In immunofluorescence microscopy of Xenopus oocytes purified antibodies against the polypeptide of 145,000 mol wt showed strong staining of nucleoli, with higher concentration in the nucleolar cortex, and of smaller nucleoplasmic bodies. In various other cells including hepatocytes, Sertoli cells, spermatogonia, and cultured kidney epithelial cells antibody staining was localized in small subnucleolar granules. The results support the conclusion that this "insoluble" protein is a major nucleus-specific protein which is specifically associated with--and characteristic of--nucleoli and certain nucleolus-related nuclear bodies. It represents the first case of a positive localization of a karyoskeletal protein in the nuclear interior, i.e. away from the pore complex-lamina structure of the nuclear cortex.
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Lipszyc JS, Phillips SG, Miller OJ. Absence of nucleolar dominance in mouse-human heterokaryons. Exp Cell Res 1981; 133:373-82. [PMID: 6165597 DOI: 10.1016/0014-4827(81)90330-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Morcillo G, de la Torre C. The effect of RNA synthesis inhibitors on prenucleolar bodies. EXPERIENTIA 1980; 36:836-7. [PMID: 6967420 DOI: 10.1007/bf01978599] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Inhibition of RNA synthesis prevents the fusion of prenucleolar bodies in the NOR region during nucleologenesis. However, their physical coalescence between themselves is increased, as shown in Allium cepa L. meristems.
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Hernandez-Verdun D, Hubert J, Bourgeois CA, Bouteille M. Ultrastructural localization of Ag-NOR stained proteins in the nucleolus during the cell cycle and in other nucleolar structures. Chromosoma 1980; 79:349-62. [PMID: 6156811 DOI: 10.1007/bf00327325] [Citation(s) in RCA: 112] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
EM investigation of Ag-AS-NOR staining after short glutaraldehyde prefixation followed by Carnoy fixation maintained good ultrastructural preservation and reactive selectivity. This enables exact localization of silver deposits both in the fibrillar centers of typical or segregated nucleoli during interphase, and in chromosome NORs during mitosis. These results argue in favour of the possibility that fibrillar centers are the interphasic counterpart of chromosome NORs. Special structures such as nucleolar blobs and remnants usually considered to be of nucleolar origin, were also stained. - These findings seem to indicate a relationship between the distribution of the silver-stained proteins, the arrangement of the nucleolar structures and the degree of nucleolar activity resulting from the experimental conditions. These results are of interest at the time when the concept of the nucleolar matrix is gradually emerging.
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Hernandez-Verdun D, Bouteille M, Ege T, Ringertz NR. Fine structure of nucleoli in micronucleated cells. Exp Cell Res 1979; 124:223-35. [PMID: 510414 DOI: 10.1016/0014-4827(79)90198-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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