T-DNA of a crown gall tumor is organized in nucleosomes

Schäfer, Willi; Weising, Kurt; Kahl, G

doi:10.1002/j.1460-2075.1984.tb01814.x

Cited by 18 publications

(9 citation statements)

References 35 publications

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“…Our results on general DNase I-sensitivity and nucleosomal organization of 3850-T-DNA confirm and extend our previous data on DNase I-sensitivity and nucleosomal organization of wild-type T-DNA in a tobacco tumor [Schafer et al, 1984;Kahl et al, 19871. They also confirm recent observations [Coates et al, 19871 that TL-and TR-DNA of a n octopine-type tumor as well as T-DNA of a nopaline-type-tumor is organized in "opened" nucleosomes and in a DNase I-sensitive state, irrespective of their actual transcription rate and the methylation of cytosine residues.…”

Section: A Prominent Dnase I-hypersensitive Site Mapssupporting

confidence: 94%

“…A detailed analysis of the chromatin structure of the various wild-type T-DNA genes, their nucleosomal patterns, their general DNase I-sensitivity, and the occurrence of DNase I-hypersensitive sites in cloned tobacco crown gall tumors incited by Agrobacterium tumefaciens has been described in previous reports [Schafer et al, 1984;Kahl et al, 19871. Similar studies on the relationship between gene expression and chromatin structure were now performed on a modified T-DNA in tobacco plants transformed with the disarmed vector plasmid pGV 3850.…”

Section: Chromatin Structure and Expression Of Modified T-dna In Tranmentioning

confidence: 98%

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Chromatin structure of transferred genes in transgenic plants

1990

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The chromatin structure of foreign genes in transgenic tobacco plants was investigated by digestion of nuclei with DNase I and micrococcal nuclease, respectively, followed by restriction and Southern analysis of the digestion products. The results were compared to the differential expression of the different transgenes. Two model systems were used: plants harbouring vector DNA derived from the disarmed vector pGV Digestion of chromatin harbouring 3850-T-DNA with micrococcal nucleose resulted in a blurred nucleosomal pattern as compared to nucleolar and bulk chromatin, the extent of blurring being independent of the expression of transferred genes.The present results favour the "permissive domain'' hypothesis which capitalizes on the chromatin surrounding the integration site as the determining factor for the chromatin structure of incoming alien genes. However, between-transformant variability of expression is not reflected by differential sensitivity to DNase I. Hence, other factors than chromatin structure must be involved in creating "position effects."

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Section: A Prominent Dnase I-hypersensitive Site Mapssupporting

confidence: 94%

Section: Chromatin Structure and Expression Of Modified T-dna In Tranmentioning

confidence: 98%

Chromatin structure of transferred genes in transgenic plants

1990

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“…The chromatin conformation of the T-DNA from the HT37#15 tumor is essentially the same as that in the E9 tumor line. The T-DNA can be found in a nucleosome conformation, a result which agrees with a report from Schafer et al (24). They have also found that the ToDNA of a different tumor line incited by the A. tumefaciens strain T37 can be found in nucleosomes.…”

Section: Discussionsupporting

confidence: 81%

Chromatin structure of integrated T-DNA in crown gall tumors

1987

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We have investigated the chromatin structure of the integrated T-DNA in two N. tabacum crown gall tumor lines, and compared the results to those obtained in a previous study of the methylation patterns of these same integrated DNA sequences (Gelvin et al., Nucleic Acids Res. 11:159-174, 1983). The E9 octopine-type tumor contains a single copy of TL, whose transcription is essential for tumor maintenance, and 15-30 copies of TR, a non-essential region. The HT37#15 nopaline type teratoma contains a single copy of the nopaline T-DNA. All these integrated sequences can be found associated with nucleosomes, although the diffuse nature of the nucleosome bands on Southern transfers implies an 'open' chromatin conformation. In addition, all the sequences are more sensitive to digestion with deoxyribonuclease I than the bulk of the chromatin. We present evidence suggesting that, despite the previously published data that the majority of copies of the TR-DNA are highly methylated at the sequence CCGG whereas the TL-DNA is not, the majority of copies of the TR-DNA in the E9 tumor line are in the same chromatin conformation as TL. These data therefore suggest that most of the copies of TR-DNA are likely to be transcriptionally competent.

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“…These conditions yielded DNA greater than 25 Kbp in length and preserved chromatin integrity as assessed by a regular and distinct nucleosome repeat 'ladder' generated upon digestion of isolated nuclei with micrococcal nuclease (MN). The bulk nucleosome repeat lenght of chromatin from maize root and leaf is 175 bp and 190 bp, respectively (data not shown), which is in agreement with that reported for tobacco (27) and other organisms (for review see 16).…”

Section: Dna Purification and Analysissupporting

confidence: 80%

Insertion of the Mu1 transposable element into the first intron of maize Adh1 interferes with transcript elongation but does not disrupt chromatin structure

Vayda

Freeling

1986

Plant Mol Biol

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The presence of the Mu1 transposable element within the first intervening sequence of the maize Adh1 gene interfered with transcription through that gene. Insertion of the element did not have an apparent effect on transcription initiation or chromatin structure. In nuclei isolated from anaerobically induced roots, in which Adh1 is transcriptionally active, a subset of the Adh1 chromatin is arranged in a unique conformation characterized by a generalized sensitivity to nucleases, specific DNAase I sensitive sites and a nucleosome array distinct from the inactive configuration present in leaf nuclei. The chromatin organization of the Mu1-induced mutant alleles is indistinguishable from that of the progenitor Adh1-S allele and a point mutant allele that is null for ADH1 activity. The initiation of transcription also proved to be unaffected in these mutants. Nuclear runoff experiments indicated that Adh1 sequences upstream from the point of Mu1 insertion were transcribed normally, but sequences downstream to the insertion were drastically reduced relative to a reference gene expressed in anaerobic root nuclei. Thus, it was concluded that the defect in these Mu1-induced mutants does not reside at the level of gene accessibility or transcript initiation. Rather, Mu1 presents an impediment to the progress of the polymerase II complex during transcript elongation.

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T-DNA of a crown gall tumor is organized in nucleosomes

Cited by 18 publications

References 35 publications

Chromatin structure of transferred genes in transgenic plants

Chromatin structure of transferred genes in transgenic plants

Chromatin structure of integrated T-DNA in crown gall tumors

Insertion of the Mu1 transposable element into the first intron of maize Adh1 interferes with transcript elongation but does not disrupt chromatin structure

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