A tobacco matrix attachment region reduces the loss of transgene expression in the progeny of transgenic tobacco plants

Ülker, Bekir; Allen, George C.; Thompson, William F.; Spiker, Steven; Weissinger, Arthur K.

doi:10.1046/j.1365-313x.1999.00453.x

Cited by 65 publications

(40 citation statements)

References 71 publications

(57 reference statements)

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“…Similar results were obtained using different transgenic lines. One set of experiments used T19 ϫ NT scions as in the above-described experiments, but the rootstocks were derived from a different GUS-silenced line (line 106; Ulker et al, 1999). The results of these grafts were nearly identical to those reported above: the 106 ϫ HC-Pro rootstock, in which PTGS was suppressed by HC-Pro, was as capable of silencing the T19 ϫ NT scion as the 106 ϫ NT rootstock (data not shown).…”

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confidence: 52%

“…The ␤-glucuronidase (GUS)-silenced lines 6b5 (Elmayan and Vaucheret, 1996) and 106 (Ulker et al, 1999) and GUS-expressing transgenic lines 23b9, 23b10 (Elmayan and Vaucheret, 1996), and T19 (English et al, 1996) have been previously described. Line U-6B (Carrington et al, 1990), carrying wild-type P1/helper component-proteinase (HC-Pro) sequence from tobacco etch virus (TEV), and control line Nicotiana tabacum cv Havana 425, carrying only the binary vector sequence, were provided by J. Carrington (Washington State University, Pullman, WA).…”

Section: Transgenic Tobacco Linesmentioning

confidence: 99%

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HC-Pro Suppression of Transgene Silencing Eliminates the Small RNAs but Not Transgene Methylation or the Mobile Signal

et al. 2001

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Post-transcriptional gene silencing (PTGS) is a sequence-specific RNA degradation mechanism that is widespread in eukaryotic organisms. It is often associated with methylation of the transcribed region of the silenced gene and with accumulation of small RNAs (21 to 25 nucleotides) homologous to the silenced gene. In plants, PTGS can be triggered locally and then spread throughout the organism via a mobile signal that can cross a graft junction. Previously, we showed that the helper component-proteinase (HC-Pro) of plant potyviruses suppresses PTGS. Here, we report that plants in which PTGS has been suppressed by HC-Pro fail to accumulate the small RNAs associated with silencing. However, the transgene locus of these plants remains methylated. Grafting experiments indicate that HC-Pro prevents the plant from responding to the mobile silencing signal but does not eliminate its ability to produce or send the signal. These results demonstrate that HC-Pro functions downstream of transgene methylation and the mobile signal at a step preceding accumulation of the small RNAs. INTRODUCTIONPost-transcriptional gene silencing (PTGS) is a sequencespecific RNA degradation mechanism first discovered in transgenic plants (Napoli et al., 1990;Smith et al., 1990;van der Krol et al., 1990). Related processes have been found in diverse eukaryotic organisms including Neurospora , in which it is called quelling, and a variety of animal systems, in which it is referred to as RNA interference or RNAi Fire, 1999;Grant, 1999;Kooter et al., 1999;Ding, 2000;Matzke et al., 2001). Sequence-specific RNA degradation is triggered by double stranded RNA (dsRNA) in a variety of organisms Waterhouse et al., 1998;Sharp, 1999;Bass, 2000;Matzke et al., 2001). In plants, PTGS can be induced by RNA viruses, many of which replicate via dsRNA intermediates. Finally, in both plants and Caenorhabditis elegans , the process can be triggered locally and then spread to distant parts of the organism (Palauqui et al., 1997;Voinnet and Baulcombe, 1997;Fire et al., 1998;Jorgensen et al., 1998;Palauqui and Vaucheret, 1998;Voinnet et al., 1998). The relatedness of these sequence-specific RNA degradation processes in different organisms is evidenced by their requirement for a conserved set of gene products Matzke et al., 2001), including a protein with homology to translation factor eIF2C (Tabara et al., 1999;Catalanotto et al., 2000;Fagard et al., 2000), an RNA-dependent RNA polymerase (RdRp) (Cogoni and Macino, 1999a;Dalmay et al., 2000;Mourrain et al., 2000;Smardon et al., 2000), and proteins with homology to DNA helicases and RNase D (Cogoni and Macino, 1999b;Ketting et al., 1999). However, at this point, neither the roles of these various gene products nor the mechanisms for induction, maintenance, and spread of sequence-specific RNA degradation are clearly understood.Several molecular features characterize the sequencespecific RNA degradation processes found in diverse organisms. Studies in both plants and Drosophila have shown that silencing is accompanied b...

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confidence: 52%

Section: Transgenic Tobacco Linesmentioning

confidence: 99%

HC-Pro Suppression of Transgene Silencing Eliminates the Small RNAs but Not Transgene Methylation or the Mobile Signal

et al. 2001

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“…Plant MARs have been implicated in a variety of gene expression phenomena (Breyne et al, 1992;Allen et al, 1993;Schöffl et al, 1993;Mlynarova et al, 1994Mlynarova et al, , 1996van der Geest et al, 1994;Iglesias et al, 1997;Matzke and Matzke, 1998;Ülker et al, 1999;Vain et al, 1999), suggesting that MARs are cis-regulatory elements. In other transgenic studies, MARs have failed to play a role as gene effectors (L. Sidorenko, W. Bruce, S. Maddock, and T. Peterson, unpublished data).…”

Section: Introductionmentioning

confidence: 99%

Suppression of Transgene Silencing by Matrix Attachment Regions in Maize

et al. 2002

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Matrix attachment regions (MARs) are DNA sequences that bind an internal nuclear network of nonhistone proteins called the nuclear matrix. Thus, they may define discrete gene-containing chromatin loops in vivo. We have studied the effects of flanking transgenes with MARs on transgene expression levels in maize callus and in transformed maize plants. Three MAR elements, two from maize ( Adh1 5 MAR and Mha1 5 MAR) and one from yeast (ARS1), had very different effects on transgene expression that bore no relation to their affinity for the nuclear matrix in vitro. In callus, two of the MAR elements ( Adh1 5 MAR and ARS1) reduced transgene silencing but had no effect on the variability of expression. In transgenic plants, Adh1 5 MAR had the effect of localizing ␤ -glucuronidase expression to lateral root initiation sites. A possible model accounting for the function of Adh1 5 MAR is discussed.

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“…These features suggest a close relationship between enhancer and MAR activities. The colocalization of enhancer and MAR sequences has been shown previously for various genes, including the murine immunoglobulin (Forrester et al, 1999;Fernández et al, 2001), the bean phaseolin (van der Geest et al, 1994), the soybean Gmhsp17.6-L (Schöffl et al, 1993), and the tobacco RB7 (Allen et al, 1996) genes.…”

Section: The Pea Pete Enhancer Colocalizes With a Marmentioning

confidence: 52%

“…Examples include MAR sequences from the bean phaseolin gene (van der Geest et al, 1994), the soybean Gmhsp17.6-L gene (Schöffl et al, 1993), and the tobacco RB7 gene (Allen et al, 1996). However, little is known about the mechanism by which these plant sequences activate transcription.…”

Section: Introductionmentioning

confidence: 99%

The Transcriptional Enhancer of the Pea Plastocyanin Gene Associates with the Nuclear Matrix and Regulates Gene Expression through Histone Acetylation

2003

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The influence of the transcriptional enhancer of the pea plastocyanin gene ( PetE ) on the acetylation of histones was examined with chromatin immunoprecipitation (ChIP) experiments using antibodies that recognize acetylated or nonacetylated histones H3 and H4. In transgenic tobacco plants containing the pea PetE promoter fused to uidA , both acetylated and nonacetylated histones H3 and H4 were present on the integrated transgene. Linking the PetE enhancer to the transgene resulted in increased ␤ -glucuronidase activity and increased amounts of acetylated histones H3 and H4 present on the promoter, suggesting that the enhancer may increase transcription by mediating the acetylation of histones. Trichostatin A and sodium butyrate, which are potent inhibitors of histone deacetylases (HDAs), activated expression from the PetE promoter by fourfold, with a concomitant increase in the acetylation states of histones H3 and H4, as determined by ChIP, indicating that the acetylation of histones has a direct positive effect on transcription. The HDA inhibitors did not increase expression from the PetE promoter when it was linked to the enhancer, consistent with preexisting hyperacetylated histones on the transgene. Mapping of histone acetylation states along the reporter gene indicated that the histones H3 and H4 associated with the promoter and the 5 Ј region of uidA were hyperacetylated in the presence of the PetE enhancer. The PetE enhancer bound to isolated tobacco nuclear matrices in vitro and was associated with the nuclear matrix in nuclei isolated from transgenic tobacco plants. These results suggest that the pea PetE enhancer activates transcription by associating with the nuclear matrix, mediating the acetylation of histones on the promoter and the nearby coding region and resulting in an altered chromatin structure.

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A tobacco matrix attachment region reduces the loss of transgene expression in the progeny of transgenic tobacco plants

Cited by 65 publications

References 71 publications

HC-Pro Suppression of Transgene Silencing Eliminates the Small RNAs but Not Transgene Methylation or the Mobile Signal

HC-Pro Suppression of Transgene Silencing Eliminates the Small RNAs but Not Transgene Methylation or the Mobile Signal

Suppression of Transgene Silencing by Matrix Attachment Regions in Maize

The Transcriptional Enhancer of the Pea Plastocyanin Gene Associates with the Nuclear Matrix and Regulates Gene Expression through Histone Acetylation

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