Transcription of DNAs of Known Sequence after Injection into the Eggs and Oocytes of Xenopus laevis

Colman, Alan

doi:10.1111/j.1432-1033.1975.tb02279.x

Cited by 40 publications

(6 citation statements)

References 43 publications

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“…The most interesting conclusions from this extensive series of experiments were (1) th at the injected genes were not rapidly broken down, a substantial fraction being present in tadpoles several days after this injection, and (2) that mouse satellite DNA which is not transcribed in mouse tissues was also not transcribed to a detectable extent in injected frog eggs. The first conclusion is consistent with the earlier finding by Colman (1975) th at the artificial DNA polymer poly[d(A -T ). d(A -T )] results in the formation of poly r(A .…”

Section: T Ranscription Of Injected D N a S In Eggssupporting

confidence: 92%

The transcription and translation of DNA injected into oocytes

Gurdon

Wyllie

Robertis

1978

Phil. Trans. R. Soc. Lond. B

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Previous work from this group has shown that purified DNA injected into frog eggs is replicated semi-conservatively (Laskey & Gurdon 1973; Ford & Woodland 1975; Laskey & Melton 1978), and that purified messenger RNA injected into eggs or oocytes is efficiently translated (Gurdon, Lane, Woodland & Marbaix 1971). For the last few years we have tried to obtain transcription of genes injected into oocytes or eggs, either as whole nuclei or as purified molecules of DNA. Genes contained in whole nuclei are transcribed and translated into recognizable proteins (Gurdon, De Robertis & Partington 1976; De Robertis, Partington, Longthorne & Gurdon 1977; further references in De Robertis, Partington & Gurdon 1978, this volume). We summarize here our evidence that purified DNA is transcribed into RNA and translated into proteins after injection into oocytes and eggs of the frog Xenopus laevis .

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Section: T Ranscription Of Injected D N a S In Eggssupporting

confidence: 92%

The transcription and translation of DNA injected into oocytes

Gurdon

Wyllie

Robertis

1978

Phil. Trans. R. Soc. Lond. B

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“…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].…”

Section: Discussionmentioning

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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“…Some kinds of injected molecules are, at least in part, efficiently and correctly transcribed [e.g. 2,[4][5][6][7][8][9][10][11][12][13][14][15]' Although difficult to quantitate, biochemical and electron microscopic evidence indicates that a large proportion of the injected DNA is not transcribed at all [2,6,8]. We became interested in the question as to whether this inactive DNA is, besides being assembled into a nucleofilament composed of a chain of nucleosomes [1][2][3], also condensed into higher order structures [e.g.…”

Section: Discussionmentioning

confidence: 99%

DNA is assembled into globular supranucleosomal chromatin structures by nuclear contents of amphibian oocytes

Scheer

Sommerville

Müller³

1980

Experimental Cell Research

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SUMMARYThe assembly of DNA into nucleosomal and supranucleosomal chromatin structures has been studied (i) by injection of circular DNA molecules (plasmids) into nuclei of Pleurodeles waltlii oocytes ; and (ii) by in vitro incubation of plasmid molecules with the supernatant fraction from oocyte nuclei of Pleurodeles and X enopus laevis, followed by purification of nucleoprotein structures formed with sucrose gradient centrifugation . [n both types of experiments , spread preparations of the newly assembled and transcriptionally inactive chromatin , examined by electron microscopy , show dense globular higher order (supranucleosomal) packing forms. Under partially relaxing (low salt) preparation conditions granular chromatin subunits of about 30 nm diameter can be seen either as widely spaced particles or in closely packed aggregates. The transcriptionally inactive endogenous chromatin of chromomeres of lampbrush chromosomes is arranged in similar higher order chromatin units. A correlation is found between the sizes of the DN A molecule probes used and the numbers of nucleosomes and higher order globules in the assembled chromatin structures. After prolonged dispersion in low salt buffers , these globular chromatin units unfold into chains of7-12 nucleosomes. The results support the concept that chromatin is arranged , under physiological ion concentrations as they are present in the nucleus , in supranucleosomal units of globular morphology.When purified DNA molecules such as viral genomes , amplified ribosomal DNA (rDNA), mitochondrial DNA (mitDNA) , or prokaryotic plasmids, with and without inserts of eukaryotic genes, are injected into nuclei of X enopus laevis oocytes, they are assembled with the stored endogenous his tones into chromatin with nucleosomal configuration [1][2][3]. Some kinds of injected molecules are, at least in part, efficiently and correctly transcribed [e.g. 2,4-15]' Although difficult to quantitate, biochemical and electron microscopic evidence indicates that a large proportion of the injected DNA is not transcribed at all [2,6,8]. We became interested in the question as to whether this inactive DNA is, besides being assembled into a nucleofilament composed of a chain of nucleosomes [1][2][3], also condensed into higher order structures [e.g. 16-18] , and how the structural organization of this newly assembled chromatin relates to that of the endogenous chromatin. In the present report we provide evidence for a compaction of DNA molecules into nucleosomes and also into higher order (supranucleosomal) structures of granular morphology. These higher order structures are observed after injection of DNA into oocyte nuclei, as well as after incubation of DNA with the supernatant fraction of oocyte nuclear homogenates. The latter in vitro Exp Cell R es 129 (1980)

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Transcription of DNAs of Known Sequence after Injection into the Eggs and Oocytes of Xenopus laevis

Cited by 40 publications

References 43 publications

The transcription and translation of DNA injected into oocytes

The transcription and translation of DNA injected into oocytes

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

DNA is assembled into globular supranucleosomal chromatin structures by nuclear contents of amphibian oocytes

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