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Verheggen C, Le Panse S, Almouzni G, Hernandez-Verdun D. Maintenance of nucleolar machineries and pre-rRNAs in remnant nucleolus of erythrocyte nuclei and remodeling in Xenopus egg extracts. Exp Cell Res 2001; 269:23-34. [PMID: 11525636 DOI: 10.1006/excr.2001.5304] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nuclear functions in erythrocytes are almost completely extinct. There is no RNA polymerase I transcription, although a remnant nucleolar structure is still present. The remnant nucleolus of Xenopus laevis erythrocytes maintains a morphologically organized structure, nearly exclusively fibrillar. In this inactive nucleolar remnant, we revealed the presence of a modified form of transcription factor UBF. Several proteins of the processing machinery such as fibrillarin, nucleolin and B23/NO38, snoRNAs U3 and U8, and partially processed preribosomal RNAs colocalized in these remnant structures. Attempts to reprogram these erythrocyte nuclei in Xenopus egg extract showed that import of several nucleolar proteins was induced while the nucleolar remnant was disorganized. UBF became abundant and showed a necklace-like distribution on the decondensed ribosomal genes. Fibrillarin, nucleolin, and snoRNAs U3 and U8, also largely imported from the extract, were associated in large prenuclear bodies scattered in the nucleoplasm. B23/NO38 was present in different small bodies formed only in the most decondensed nuclei. In these remodeled erythrocyte nuclei, there was no imported preribosomal RNA and the initial presence of a residual nucleolar structure containing several partners of ribosome biogenesis was not sufficient to promote reassembly of newly imported nucleolar machineries. These nuclei, which reproduce the early events of nucleogenesis are also transcriptionally silent and thus compare to the early embryonic nuclei of Xenopus laevis.
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Affiliation(s)
- C Verheggen
- Institut Jacques Monod, UMR 7592, Paris, France
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Abstract
Cell ghosts have been prepared from mature chicken erythrocytes using 0.05% saponin. Such preparations are capable of incorporating label from [3H]UTP and provide a system, where the nucleus is permeable to nucleotides and macromolecules, for studying the low-level RNA synthesis characteristic of these cells. RNase A (50 micrograms/ml) eliminated all radioactivity binding to DE-81 filters, indicating that the product was RNA; and DNase (10 micrograms/ml) and actinomycin D (10 micrograms/ml) each inhibited UMP incorporation by 70%, suggesting that the synthesis was DNA-dependent. Polymerization was inhibited 90% by 0.1 microgram/ml alpha-amanitin, and maximum synthesis occurred in the presence of high salt (0.175 M KCl) and Mn2+ (0.5 mM). Polyacrylamide gel electrophoresis indicated that the newly synthesized RNA was heterogeneous in size, having a distribution from 5 to 60 S with a significant fraction migrating as 8-12 S. Approximately 15% of the total RNA was bound by an oligo(dT)-cellulose column, suggesting that some RNA processing was occurring, although attempts to detect the incorporation of label from [alpha-32P]GTP into a 5'-cap structure were unsuccessful. In comparison to RNA synthesis in reticulocyte nuclei, both the rate and extent of transcription in erythrocyte nuclei were much reduced. Moreover, about 25-30% of the reticulocyte nascent RNA was released from the nuclei during a 60-min incubation, while no release was observed for the erythrocyte nuclei. Hybridization of radiolabeled RNA to excess chicken DNA indicated that the majority (80%) of the in vitro transcripts were complementary to unique sequence DNA (C0t1/2 = 4.5 X 10(3)). When RNA synthesized by either erythrocyte or reticulocyte nuclei was hybridized to cDNA complementary to reticulocyte polysomal mRNA, about 8% of the reticulocyte nuclear RNA but less than 1% of the erythrocyte nuclear RNA were resistant to RNase A digestion. Taken together, these data suggest that nuclei prepared by saponin lysis of chicken erythrocytes synthesize messenger-like RNA via endogenous polymerase II activity. A fraction of this RNA is polyadenylated but contains few, if any, globin sequences or other transcripts found on reticulocyte polysomes.
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Ringertz NR, Nyman U, Bergman M. DNA replication and H5 histone exchange during reactivation of chick erythrocyte nuclei in heterokaryons. Chromosoma 1985; 91:391-6. [PMID: 3996104 DOI: 10.1007/bf00291013] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fusion of terminally differentiated chick erythrocytes (CE) with replicating quail myoblasts or established L6J1 rat myoblasts results in reactivation of DNA synthesis in the dormant CE nuclei and in suppression of DNA synthesis in the myoblast nuclei. The nuclei of primary quail myoblasts are more effectively inhibited than the nuclei of established rat myoblasts. Inhibition of DNA replication occurs not only by preventing G1 nuclei from entering S-phase but also by blocking nuclei in S-phase and by delaying nuclei in G2 from undergoing mitosis and starting a new DNA replication cycle. No inhibition of DNA synthesis could be observed when mouse erythrocytes, i.e., erythrocytes lacking nuclei, were fused with rat myoblasts to generate mouse-globin-containing L6J1 cybrids.--Reactivation of CE nuclei is associated with a loss of the tissue-specific H5 histone variant. Complete elimination of H5 histone, however, does not seem to be a necessary prerequisite for the initiation or completion of DNA replication in CE nuclei since H5 antigens are found on reactivated G1, S, and G2 nuclei.
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Dabauvalle MC, Franke WW. Karyophobic proteins. A category of abundant soluble proteins which accumulate in the cytoplasm. Exp Cell Res 1984; 153:308-26. [PMID: 6539709 DOI: 10.1016/0014-4827(84)90603-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cytoplasm of oocytes of Xenopus laevis is enriched in several soluble proteins which are either absent from the nucleus or are present there at very low concentrations. These molecules, collectively referred to as karyophobic (from the Greek verbs and which are meant here in the sense of "to be afraid of" or "to avoid") proteins represent more than 20% of the total soluble cytoplasmic proteins and include some of the most abundant soluble cellular components. They may be recovered from high-speed supernatant (S-100) fractions and, following sucrose gradient centrifugation, most of them appear in the form of complexes smaller than 8.5 S. On denaturation in urea and two-dimensional gel electrophoresis these proteins appear to be comprised of polypeptides of widely different sizes (ca Mr 15 000-230 000) and isoelectric points covering a broad range of pH values (4.2-8.0). Gel filtration and isoelectric focusing of native karyophobic proteins show that the majority occur in acidic complexes smaller than Mr 150 000, including one case of a small karyophobic protein (C9; Mr 30 000). In contrast to karyophilic proteins and proteins equilibrating between nucleus and cytoplasm karyophobic soluble proteins from [35S]methionine-labelled ooplasms, when injected into unlabelled oocytes, remain in the cytoplasm. Human proteins with a similar karyophobic behaviour have been identified in fractions of soluble proteins from HeLa cells; there, the major karyophobic protein (HCa Mr 36 000) is also one of the most abundant soluble proteins. We conclude that the specific nucleocytoplasmic compartmentalization of soluble proteins is governed not only by the principles of exclusion of large molecules from nuclear uptake and the existence of karyophilic signals in certain proteins but that a series of soluble, globular proteins exist in the cytoplasm, which have other molecular features which selectively exclude them from distribution over the nucleus. The possible functional role of the selective enrichment of these abundant proteins, which so far have escaped attention, in establishing a cytoplasmic milieu is discussed.
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Nyman U, Lanfranchi G, Bergman M, Ringertz NR. Changes in nuclear antigens during reactivation of chick erythrocyte nuclei in heterokaryons. J Cell Physiol 1984; 120:257-62. [PMID: 6205000 DOI: 10.1002/jcp.1041200221] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Reactivation of dormant chick erythrocyte (CE) nuclei was studied by fusing chick red cells with rat myoblasts, HeLa cells, and chick fibroblasts. Heterokaryons representing different stages of nuclear reactivation were fixed and examined for nuclear antigens using polyclonal patient autoantisera reacting with mammalian (human, mouse, and rat) nuclear envelope, nucleoplasm, and chromatin (DNA) antigens. Reactivation of CE nuclei was associated with marked changes in nuclear antigenicity. In rat myoblast and HeLa heterokaryons the CE nuclei acquired mammalian nucleoplasmic and nuclear envelope antigens in the corresponding nuclear subcompartments. Drastic changes in nuclear antigenicity were noted also in heterokaryons stained with DNA antisera. The compact chromatin of nuclei in mature chick erythrocytes showed little binding of DNA antibodies. Isolated nuclei on the other hand gave a strong immunofluorescence. CE nuclei in heterokaryons were strongly positive during the early stages of nuclear reactivation but then exhibited decreased reactivity. An unexpected finding was a marked reduction in the capacity of mammalian nuclei in heterokaryons to bind DNA-antibodies. This observation is discussed in relation to the previous finding that in CE-heterokaryons these nuclei often show reduced transcription and replication. The present results indicate that in heterokaryons both types of nuclei exchange macromolecules of regulatory importance via the common cytoplasm.
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Scheer U, Lanfranchi G, Rose KM, Franke WW, Ringertz NR. Migration of rat RNA polymerase I into chick erythrocyte nuclei undergoing reactivation in chick-rat heterokaryons. J Biophys Biochem Cytol 1983; 97:1641-3. [PMID: 6355125 PMCID: PMC2112706 DOI: 10.1083/jcb.97.5.1641] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Transcriptionally inactive chick erythrocyte nuclei were reactivated by Sendai virus-induced fusion of erythrocytes with rat L6J1 myoblasts. We used antibodies to trace the appearance of a specific protein engaged in transcription of a defined class of genes, those coding for rRNA, during reactivation. Using immunofluorescence microscopy, we found increasing amounts of rat RNA polymerase I to appear, during a certain period of time after fusion, in the reforming nucleoli of the chick nuclei. Amounts of rat RNA polymerase I sufficient to be detected by immunofluorescence microscopy had accumulated in the newly developed chick nucleoli 72-190 h after fusion was initiated. This time interval coincides with the time when chick rRNA synthesis can first be detected. The results raise the possibility that during these stages of the reactivation process chick rRNA genes are transcribed by heterologous RNA polymerase I molecules of rat origin.
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Globin synthesis in hybrid cells constructed by transplantation of dormant avian erythrocyte nuclei into enucleated fibroblasts. Mol Cell Biol 1982. [PMID: 7346715 DOI: 10.1128/mcb.1.12.1163] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polypeptides synthesized by mature embryonic erythrocytes prepared from the peripheral blood of 14- to 15-day-old chicken embryos were analyzed by two-dimensional gel electrophoresis. Fewer than 200 species of polypeptides were detected; the major polypeptides made at this time were identified as the alpha A-, alpha D-, and beta-globin chains. The dormant erythrocyte nuclei were next reactivated to transcriptional competence by transplantation into enucleated mouse or chicken embryo fibroblasts, with frequencies of cytoplast renucleation of about 50 and 90%, respectively. Since large numbers of hybrid cells could be constructed, a biochemical analysis was possible. Electrophoretic analysis of the [35S]methionine-labeled polypeptides made in the hybrid cell types showed that polypeptides having the mobilities of only two (alpha A and alpha D) of the three major adult globin chains were made as major constituents of the hybrid cells. However, analysis of 14C-amino acid-labeled polypeptides revealed that a beta-like polypeptide that lacked methionine was also synthesized in large amounts. This polypeptide was tentatively identified as the early embryonic globin species rho. Globin synthesis was detected as early as 3 h after nuclear transplantation and as late as 18 h, the last time measured in these experiments. It appeared that globin polypeptides made at very early times were translated at least partially from chicken messenger ribonucleic acid introduced into the hybrid cells during fusion, whereas those made at later times were translated primarily from newly synthesized globin messenger ribonucleic acid. The potential usefulness of this hybrid cell system in analyzing mechanisms regulating globin gene expression is discussed.
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Zuckerman SH, Linder S, Ringertz NR. Transcription of chick genes by mammalian RNA polymerase II in chick erythrocyte-mammalian cell heterokaryons. J Cell Physiol 1982; 113:99-104. [PMID: 7130293 DOI: 10.1002/jcp.1041130117] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The introduction of chick erythrocyte nuclei into mammalian cell cytoplasms results in their reactivation as evidenced by the de novo transcription of chick genes and the synthesis of both globin and constitutive proteins. In the present study, chick erythrocytes have been fused to L6 rat myoblasts and to alpha-amanitin-resistant variants of L6 to determine whether the chick or the mammalian RNA polymerase II was responsible for transcription of chick genes. Heterokaryons formed by fusing chick erythrocytes with alpha-amanitin-resistant L6 myoblasts synthesize both chick globin and chick constitutive proteins in the continued presence of 5 micrograms/ml alpha amanitin ten days postfusion. Both the synthesis of globin and other chick polypeptides occurs at levels comparable to those observed for untreated heterokaryons. Synthesis occurs under conditions in which insignificant chick RNA polymerase II activity can be detected in wild-type heterokaryons by autoradiography. These results demonstrate that RNA polymerase II is one of the mammalian proteins that is selectively taken up by the chick nucleus during reactivation in the presence of alpha amanitin. Furthermore, the mammalian RNA polymerase II alone can account for the transcription of both differentiation specific and constitutive genes in the chick nucleus.
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Van der Veer E, Bootsma D. Repair DNA synthesis in heterokaryons during reactivation of chick erythrocytes fused with human diploid fibroblasts or HeLa cells. Exp Cell Res 1982; 138:469-74. [PMID: 6176461 DOI: 10.1016/0014-4827(82)90202-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Bootsma D, Keijzer W, Van der Veer E, Rainaldi G, De Weerd-Kastelein EA. Interaction of human and chick DNA repair functions in UV-irradiated xeroderma pigmentosum-chick erythrocyte heterokaryons. Exp Cell Res 1982; 137:181-9. [PMID: 7056283 DOI: 10.1016/0014-4827(82)90019-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Bruno J, Reich N, Lucas JJ. Globin synthesis in hybrid cells constructed by transplantation of dormant avian erythrocyte nuclei into enucleated fibroblasts. Mol Cell Biol 1981; 1:1163-76. [PMID: 7346715 PMCID: PMC369742 DOI: 10.1128/mcb.1.12.1163-1176.1981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The polypeptides synthesized by mature embryonic erythrocytes prepared from the peripheral blood of 14- to 15-day-old chicken embryos were analyzed by two-dimensional gel electrophoresis. Fewer than 200 species of polypeptides were detected; the major polypeptides made at this time were identified as the alpha A-, alpha D-, and beta-globin chains. The dormant erythrocyte nuclei were next reactivated to transcriptional competence by transplantation into enucleated mouse or chicken embryo fibroblasts, with frequencies of cytoplast renucleation of about 50 and 90%, respectively. Since large numbers of hybrid cells could be constructed, a biochemical analysis was possible. Electrophoretic analysis of the [35S]methionine-labeled polypeptides made in the hybrid cell types showed that polypeptides having the mobilities of only two (alpha A and alpha D) of the three major adult globin chains were made as major constituents of the hybrid cells. However, analysis of 14C-amino acid-labeled polypeptides revealed that a beta-like polypeptide that lacked methionine was also synthesized in large amounts. This polypeptide was tentatively identified as the early embryonic globin species rho. Globin synthesis was detected as early as 3 h after nuclear transplantation and as late as 18 h, the last time measured in these experiments. It appeared that globin polypeptides made at very early times were translated at least partially from chicken messenger ribonucleic acid introduced into the hybrid cells during fusion, whereas those made at later times were translated primarily from newly synthesized globin messenger ribonucleic acid. The potential usefulness of this hybrid cell system in analyzing mechanisms regulating globin gene expression is discussed.
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Gregory SP, Maclean N, Pocklington MJ. Artificial modification of nuclear gene activity. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1981; 13:1047-63. [PMID: 6170533 DOI: 10.1016/0020-711x(81)90167-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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14
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Schwab IA, Luger O. Reinitiation of DNA synthesis in postmitotic nuclei of myotubes by virus-mediated fusion with embryonic fibroblasts. Differentiation 1980; 16:93-9. [PMID: 7429072 DOI: 10.1111/j.1432-0436.1980.tb01063.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Myotubes, whose nuclei have stopped DNA synthesis were fused with replicative embryonic fibroblasts. In heterokaryons the postmitotic muscle nuclei resumed DNA synthesis. Incorporation of radioactive thymidine into muscle, and also into fibroblast nuclei was dependent upon the time elapsed between virus-mediated fusion and administration of radioactive thymidine. Whereas incorporation into fibroblast nuclei diminished with time, there was an early increase of labelling into muscle nuclei followed by a decrease of incorporation of 3H thymidine. DNA synthesis was also dependent upon the ratio of noncycling (muscle) to cycling (fibroblast) nuclei. There was a greater incorporation of 3H thymidine into muscle and fibroblast nuclei in myotubes containing larger numbers of fibroblast nuclei. A model is discussed for the control of DNA synthesis in polykaryocytes derived from fusion of cycling and noncycling cells.
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Hernandez-Verdun D, Bouteille M. Nucleologenesis in chick erythrocyte nuclei reactivated by cell fusion. JOURNAL OF ULTRASTRUCTURE RESEARCH 1979; 69:164-79. [PMID: 40045 DOI: 10.1016/s0022-5320(79)90107-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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Hentschel CC, Tata JR. Template-engaged and free RNA polymerases during Xenopus erythroid cell maturation. Dev Biol 1978; 65:496-507. [PMID: 680374 DOI: 10.1016/0012-1606(78)90044-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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18
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Tsutsui Y, Chang SD, Baserga R. Failure of reactivation of chick erythrocytes after fusion with temperature-sensitive mutants of mammalian cells arrested in G1. Exp Cell Res 1978; 113:359-67. [PMID: 400911 DOI: 10.1016/0014-4827(78)90376-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Two temperature-sensitive (ts) mutants of mammalian cell lines (AF8 and cs4D3) that arrest in G1 at the nonpermissive temperature were fused with chick erythrocytes and the induction of DNA synthesis was studied in the resulting heterokaryons. While both AF8 and cs4D3 could induce DNA synthesis in chick nuclei at the permissive temperature, they both failed to do so when arrested in G1 at the nonpermissive temperature. When S phase AF8 cells were fused with chick erythrocytes, chick nuclei were reactivated even if the heterokaryons were incubated at the temperature nonpermissive for AF8. A third ts mutant, ts111, that is blocked in cytokinesis but continues to synthesize DNA, reactivated chick nuclei at both permissive and nonpermissive temperature. It is concluded that chick erythrocyte reactivation depends on the presence of S phase-specific factors.
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Affiliation(s)
- Y Tsutsui
- Department of Pathology, Temple University School of Medicine, Philadelphia, PA 19140
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Moore GP. Embryonic diapause in the marsupial Macropus eugenii. Stimulation of nuclear RNA polymerase activity in the blastocyst during resumption of development. J Cell Physiol 1978; 94:31-6. [PMID: 618903 DOI: 10.1002/jcp.1040940105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Darzynkiewicz Z, Traganos F, Sharpless T, Melamed MR. DNA denaturation in situ. Effect of divalent cations and alcohols. J Cell Biol 1976; 68:1-10. [PMID: 1245542 PMCID: PMC2109610 DOI: 10.1083/jcb.68.1.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Heat denaturation profiles of rat thymus DNA, in intact cells, reveal the presence of two main DNA fractions differing in sensitivities to heat. The thermosensitive DNA fraction shows certain properties similar to those of free DNA: its stability to heat is decreased by alcohols and is increased in the presence of the divalent cations Ca2+, Mn2+, or Mg2+ at concentrations of 0.1-1.0 mM. Unlike free DNA, however, this fraction denatures over a wide range of temperature, and is heterogeneous, consisting of at least two subfractions with different melting points. The thermoresistant DNA fraction shows lowered stability to heat in the presence of Ca2+, Mn2+, or Mg2+ and increased stability in the presence of alcohols. It denatures within a relatively narrow range of temperature, consists of at least three subfractions, and, most likely, represents DNA masked by histones. The effect of Ca2+, Mn2+, or Mg2+ in lowering the melting point of the thermoresistant DNA fraction is seen at cation concentrations comparable to those required to maintain gross chromatin structure in cell nuclei or to support superhelical DNA conformation in isolated chromatin (0.5-1.0 mM). It is probable that factors involved in the maintenance of gross chromatin organization in situ and/or related to DNA superhelicity also have a role in modulating DNA-histone interactions, and that DNA-protein interactions as revealed by conventional methods using isolated chromatin may be different from those revealed when gross chromatin morphology remains intact.
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Sidebottom E, Deák II. The function of the nucleolus in the expression of genetic information: studies with hybrid animal cells. INTERNATIONAL REVIEW OF CYTOLOGY 1976; 44:29-53. [PMID: 177380 DOI: 10.1016/s0074-7696(08)61646-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Berezney R, Coffey DS. The nuclear protein matrix: isolation, structure, and functions. ADVANCES IN ENZYME REGULATION 1976; 14:63-100. [PMID: 970274 DOI: 10.1016/0065-2571(76)90008-x] [Citation(s) in RCA: 112] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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25
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Zeuthen J. Heterokaryons in the analysis of genes and gene regulation. HUMANGENETIK 1975; 27:275-301. [PMID: 168148 DOI: 10.1007/bf00278421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cytological and chemical analysis of heterokaryons, the immediate product of cell fusion, offer new possibilities for studying the factors responsible for genetic regulation in eukaryotic cells. In comparison with proliferating cell hybrids the heterokaryon state offers the important advantage that a heterokaryon contains two complete genomes since chromosome loss does not occur, but since segregation and recombination are absent, heterokaryons cannot be used for gene mapping in the same way as proliferating cell hybrids. However, if two cell types carrying different genetic defects are fused the analysis can be used for studies of gene complementation. The biological information obtained with heterokaryons has emphasized the role of the cytoplasm in the control of nuclear activity. When a G1 nucleus is brought into contact with the cytoplasm of an S phase cell the G1 nucleus is stimulated to synthesize DNA. If the nucleus is brought into a mitotic cell, the chromatin of the G1 nucleus is forced to condense into prematurely condensed chromosomes. Inactive nuclei such as the dormant chick erythrocyte nucleus will be stimulated to initiate RNA and DNA synthesis when brought into contact with an active cytoplasm by cell fusion. Specific nuclear proteins have been shown to be responsible for this process of reactivation. Other inactive nuclei such as the nuclei of macrophages and spermatozoa have likewise been shown to be reactivated by fusion with active cells. The degree of activation in all of these cases appears to be determined by the state of the active cell. Inactive nuclei are activated to the same level as the active nucleus but seldom beyond this level. If differentiated cells are fused with undifferentiated cells, usually the differentiated character is lost rapidly after fusion. This observation is in agreement with several studies on proliferating cell hybrids indicating some type of negative control of differentiated properties. In heterokaryons obtained by fusion of cells of a similar type of histotypic differentiation usually coexpression of the differentiated markers is observed.
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Gordon S. Cell fusion and some subcellular properties of heterokaryons and hybrids. J Biophys Biochem Cytol 1975; 67:257-80. [PMID: 1104638 PMCID: PMC2109606 DOI: 10.1083/jcb.67.2.257] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Clements GB, Subak-Sharpe JH. Reactivation of chick erythrocyte nuclei in BHK derived cells with multiple biochemical lesions. Exp Cell Res 1975; 95:15-24. [PMID: 1193144 DOI: 10.1016/0014-4827(75)90603-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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28
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Krause MO, Kleinsmith LJ, Stein GS. Properties of the genome in normal and SV-40 transformed WI-38 human diploid fibroblasts. III. Turnover of nonhisone chromosomal proteins and their phosphate groups. Life Sci 1975; 16:1047-58. [PMID: 166261 DOI: 10.1016/0024-3205(75)90189-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Norwood TH, Pendergrass WR, Martin GM. Reinitiation of DNA synthesis in senescent human fibroblasts upon fusion with cells of unlimited growth potential. J Cell Biol 1975; 64:551-6. [PMID: 1150745 PMCID: PMC2109544 DOI: 10.1083/jcb.64.3.551] [Citation(s) in RCA: 89] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Postreplicative, "senescent" human fibroblasts were fused to HeLa or to SV-40 transformed human fibroblasts with Sendai virus. DNA synthesis was reinitiated in senescent nuclei in a high proportion of the heterodikaryons. The [3H]thymidine labeling index of senescent fibroblast nuclei in heteropolykaryons was a function of the ratio of HeLa to senescent nuclei.
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Ege T, Zeuthen J, Ringertz NR. Reactivation of chick erythrocyte nuclei after fusion with enucleated cells. SOMATIC CELL GENETICS 1975; 1:65-80. [PMID: 194345 DOI: 10.1007/bf01538732] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inactivated Sendai virus was used to fuse nucleated chick erythrocytes with mouse L and A9 cells which had been enucleated by centrifugation in the presence of cytochalasinB. The enucleation step removed the nuclei from more than 99% of the cells. During the fusion step, chick erythrocyte nuclei were introduced into 20% of the enucleated mouse cytoplasms. This resulted in the formation of a large number of "reconstituted cells" where practically all the cytoplasm originated from the mouse cell while the nucleus was of chick origin. The chick erythrocyte nuclei appeared to become well integrated into the mouse cytoplasms since they increased dramatically in size and dry mass, formed nucleolus-like bodies, and resumed RNA synthesis. This, however, did not prevent a gradual decrease in the rate of protein synthesis in the cytoplasm after the removal of the mouse nucleus. Protein synthesis decayed at a similar rate in both reconstituted and enucleated cells. The majority of these "cells" died within 48 h and all of them within 5 days after enucleation/fusion. By contrast, the small number of L cells which failed to become enucleated multiplied rapidly. The results obtained suggest that the reactivation of the chick erythrocyte nuclei is not fast enough to rescue the enucleated mouse cytoplasms.
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Zetterberg A, Auer G, Moore GP. Effect of plasma membrane contacts between cells on uridine incorporation and RNA polymerase activity. Exp Cell Res 1974; 88:382-7. [PMID: 4473368 DOI: 10.1016/0014-4827(74)90256-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Moore GP, Auer G, Zetterberg A. Reactivation of nuclear RNA polymerase activity in growth stimulated epithelial cells. Exp Cell Res 1974; 88:375-81. [PMID: 4139028 DOI: 10.1016/0014-4827(74)90255-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Darzynkiewicz Z, Chelmicka-Szorc E, Arnason BG. Suppressive effect of protease inhibitors on heterokaryons containing chick erythrocyte nuclei. Exp Cell Res 1974; 87:333-45. [PMID: 4472333 DOI: 10.1016/0014-4827(74)90489-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Zakai N, Loyter A, Kulka RG. Fusion of erythrocytes and other cells with retention of erythrocyte cytoplasm: nuclear activation in chicken erythrocyte-melanoma heterokaryons. J Cell Biol 1974; 61:241-8. [PMID: 4362138 PMCID: PMC2109254 DOI: 10.1083/jcb.61.1.241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Appels R, Bolund L, Gato S, Ringertz NR. The kinetics of protein uptake by chick erythrocyte nuclei during reactivation in chick-mammalian heterokaryons. Exp Cell Res 1974; 85:182-90. [PMID: 4597132 DOI: 10.1016/0014-4827(74)90229-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Goto S, Ringertz NR. Preparation and characterization of chick erythrocyte nuclei from heterokaryons. Exp Cell Res 1974; 85:173-81. [PMID: 4363804 DOI: 10.1016/0014-4827(74)90228-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Carlsson SA, Ringertz NR, Savage RE. Intracellular antigen migration in interspecific myoblast heterokaryons. Exp Cell Res 1974; 84:255-66. [PMID: 4361716 DOI: 10.1016/0014-4827(74)90404-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Darzynkiewicz Z, Chelmicka-Szorc E, Arnason BG. Chick-erythrocyte nucleus reactivation in heterokaryons: suppression by inhibitors of proteolytic enzymes. Proc Natl Acad Sci U S A 1974; 71:644-7. [PMID: 4522779 PMCID: PMC388068 DOI: 10.1073/pnas.71.3.644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Reactivation of chick-erythrocyte nuclei in heterokaryons (obtained by Sendai virus-induced fusion of chick erythrocytes with HeLa cells) is suppressed by specific inhibitors of trypsin and trypsin-like enzymes. N-alpha-tosyl-L-lysyl-chloromethane and N-alpha-tosyl-L-arginine methylester inhibit erythrocyte nuclear enlargement and suppress RNA and DNA synthesis in nuclei of erythrocytes and HeLa cells in heterokaryons at concentrations that only minimally influence individual HeLa cells or HeLa homokaryons. Although other unknown mechanisms of action cannot be formally excluded, the data are interpreted as fitting best with an intracellular site of action of the protease inhibitors studied, and as suggesting a role for cellular proteases in reactivation of chick-erythrocyte nuclei in heterokaryons.
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Coffey DS, Barrack ER, Heston WD. The regulation of nuclear DNA template restrictions by acidic polymers. ADVANCES IN ENZYME REGULATION 1974; 12:219-66. [PMID: 4618431 DOI: 10.1016/0065-2571(74)90016-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Krawczyńska W, Przelecka A. Decondensation of nuclear chromatin under the influence of Tris buffer. EXPERIENTIA 1973; 29:1277-80. [PMID: 4758941 DOI: 10.1007/bf01935116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Davis FM, Adelberg EA. Use of somatic cell hybrids for analysis of the differentiated state. BACTERIOLOGICAL REVIEWS 1973; 37:197-214. [PMID: 4581783 PMCID: PMC413811 DOI: 10.1128/br.37.2.197-214.1973] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Auer G, Moore GP, Ringertz NR, Zetterberg A. DNA-dependent RNA synthesis in nuclear chromatin of fixed cells: relationship between dye-binding properties, nuclear protein content and RNA polymerase activity. Exp Cell Res 1973; 76:229-33. [PMID: 4734182 DOI: 10.1016/0014-4827(73)90440-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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