Morphological Studies of Transcription

Miller, O. L.; Bakken, Aimée H.

doi:10.1530/acta.0.071s155

Cited by 352 publications

(183 citation statements)

References 6 publications

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“…In particular, vitellogenic stages are characterized by maximal transcription of nucleolar genes and of the protein-coding genes located in the lateral loops of lampbrush chromosomes. Transcription units of both kinds of genes can be readily visualized by electron microscopy of spread preparations (Miller and Beatty, 1969;Miller and Bakken, 1972;Miller, 1981;Scheer et aI., 1979b;Scheer and Zentgraf, 1982). In addition, transcribed lampbrush chromosome loops are easily recognized in the light microscope (e.g., Callan and Lloyd, 1960;Call an , 1982;LaCroix, 1968) and their presence is directly related to the transcriptional process.…”

Section: Resultsmentioning

confidence: 99%

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Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Scheer

Hinssen

Franke

et al. 1984

Cell

283

155

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SummaryNuclei of amphibian oocytes contain large amounts of actin, mostly in unpolymerized or short-polymer form. When antibodies to actin or actin-binding proteins (fragmin and the actin modulator from mammalian smooth muscle) are injected into nuclei of living oocytes of Pleurodeles waltlii, transcription of the lampbrush chromosomes, but not of the rRNA genes, is inhibited. When transcription is repressed by drugs or RNA is digested by microinjection of RNAase into oocyte nuclei, an extensive meshwork of actin filament bundles is seen in association with the isolated lampbrush chromosomes. These observations indicate a close relationship between the state of nuclear actin and transcriptional activity and suggest that nuclear actin may be involved in transcriptional events concerning protein-coding genes.

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Section: Resultsmentioning

confidence: 99%

“…Ultrathin sections were stained according to standard procedures. Chromatin spread preparations were made essentially according to the method of Miller and Bakken (1972) with some modifications (Scheer, 1978;Scheer et aI. , 1976Scheer et aI.…”

Section: Electron Microscopymentioning

confidence: 99%

Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Scheer

Hinssen

Franke

et al. 1984

Cell

283

155

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“…Nuclear contents were allowed to disperse under very low salt conditions (0.1 mM sodium borate buffer, pH 8.0 or 9.0; cf [31]) , centrifllged, stained and shadow-cast as described [7 , 31 -33].…”

Section: Spreading Proceduresmentioning

confidence: 99%

Mitochondrial DNA arranged into chromatin-like structures after injection into amphibian oocyte nuclei

Zentgraf

Trendelenburg

Spring

et al. 1979

Experimental Cell Research

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SUMMARYPurified mitochondrial DNA (mitDNA) from ovaries ofXenopus lae vis was injected into the nuclei (germinal vesicles) of large viteUogenic oocytes of the same organism and examined by electron microscopy ofthe spread nuclear contents. Normally located nuclei of untreated oocytes as weil as peripherally translocated nuclei of centrifuged oocytes were used. In addition, oocyte nuclei isolated and incubated under liquid paraffin oil were injected with DNA . The integrity oftranscriptional structures of endogenous chromosomal (Iampbrush chromosomes) and extrachromosomal (nucleoli) genes of the injected nuclei was demonstrated . Microinjected mitDN A was identified as circles of chromatin exhibiting polynucleosome-like organization and a me an contour length of 2.6 J.Lm, corresponding to a compaction ratio of the mitDN A of about 2 : I. This DNA packing ratio is similar to that observed after preparation of various kinds of native chromatin in low salt buffers . The chromatin circles formed from injected mitDNA only very rarely exhibited lateral fibrils suggestive of transcriptional activity. These results suggest that purified mitDNA can be transformed to normally structured chromatin when exposed to oocyte nuclear contents but is rarely , if at all , transcribed in this form and in this environment. Circular double-stranded DN A molecules injected into oocyte nuclei of Xenopus laevis are relatively stable and can be assembled into chromatin-like configurations. This has been demonstrated for SV40 DNA [1][2][3][4][5], plasmid DNA [6] and extrachromosomal ribosomal DNA (rDNA) from an insect [7]. Moreover, transcription of genes contained in such injected DNA molecules has been demonstrated [8] , e.g., for SV40 DNA [9][10][11][12][13] , and for various plasmids such as those containing genes coding for histones of Drosophila [9,11] or sea urchin [14][15][16], genes coding for 5S rRNA ofXenopus [17], genes coding for tRN As of a nematode [18] or Xenopus laevis [15,19], and a plasmid containing a major portion of the pre-rRNA gene of Xenopus [6]. Transcription of DNA injected into Xenopus oocyte nuclei has also been demonstrated for the naturally occurring circular pre-rRNA genes from ovaries of the water beetle, Dytiscus marginalis [7]. In the present study we show that another eukaryotic kind of circular DNA, which in nature is not associated with histones and nuclear transcriptional complexes , namely the mitochondrial genome, can be organized into Exp Cell Res 122 (/979 )

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“…The different Pols are defined by different drug sensitivities, nuclear localization, and the genes they transcribe. In mammalian cells, each transcription unit is transcribed by only one (or a few) pol II enzymes (Jackson et al, 1998;Miller and Bakken, 1972). As pol II factories contain about eigth active pols (Pombo et al, 1999b), this suggests that each simultaneously transcribes 8 different transcription units.…”

Section: Introductionmentioning

confidence: 99%

Nanostructure of specific chromatin regions and nuclear complexes

Mathée

Baddeley

Wotzlaw

et al. 2005

Histochem Cell Biol

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Spatially Modulated Illumination (SMI) microscopy is a method of widefield fluorescence microscopy featuring interferometric illumination, which delivers structural information about nanoscale features in fluorescently labeled cells. Using this approach, structural changes in the context of gene activation and chromatin remodeling may be revealed. In this paper we present the application of SMI microscopy to size measurements of the 7q22 gene region, giving us a size estimate of 105 ± 16nm which corresponds to an average compaction ratio of 1:324. The results for the 7q22 domain are compared with the previously measured sizes of other fluorescently labeled gene regions, and to those obtained for transcription factories. The absence of a correlation between the measured and genomic sizes of the various gene regions indicate that a high variability in chromatin folding is present, with factors other than the sequence length contributing to the chromatin compaction. Measurements of the 7q22 region in different preparations and at different excitation wavelengths show a good agreement, thus demonstrating that the technique is robust when applied to biological samples.

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Morphological Studies of Transcription

Cited by 352 publications

References 6 publications

Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes

Mitochondrial DNA arranged into chromatin-like structures after injection into amphibian oocyte nuclei

Nanostructure of specific chromatin regions and nuclear complexes

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