Transcriptional gene silencing in plants

In plants, silencing is usually accompanied by DNA methylation and heterochromatic histone marks. We studied these epigenetic modifications in different epialleles of 35S promoter (P35S)-driven tobacco transgenes. In locus 1, the T-DNA was organized as an inverted repeat, and the residing neomycin phosphotransferase II reporter gene (P35S-nptII) was silenced at the posttranscriptional (PTGS) level. Transcriptionally silenced (TGS) epialleles were generated by trans-acting RNA signals in hybrids or in a callus culture. PTGS to TGS conversion in callus culture was accompanied by loss of the euchromatic H3K4me3 mark in the transcribed region of locus 1, but this change was not transmitted to the regenerated plants from these calli. In contrast, cytosine methylation that spread from the transcribed region into the promoter was maintained in regenerants. Also, the TGS epialleles generated by trans-acting siRNAs did not change their active histone modifications. Thus, both TGS and PTGS epialleles exhibit euchromatic (H3K4me3 and H3K9ac) histone modifications despite heavy DNA methylation in the promoter and transcribed region, respectively. However, in the TGS locus (271), abundant heterochromatic H3K9me2 marks and DNA methylation were present on P35S. Heterochromatic histone modifications are not automatically installed on transcriptionally silenced loci in tobacco, suggesting that repressive histone marks and cytosine methylation may be uncoupled. However, transient loss of euchromatic modifications may guide de novo DNA methylation leading to formation of stable repressed epialleles with recovered eukaryotic marks. Compilation of available data on epigenetic modification of inactivated P35S in different systems is provided.

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“…TGS is usually accompanied by heterochromatic histone marks and cytosine methylation (reviewed in refs 6 , 62 , 63 …”

Section: Discussionmentioning

confidence: 99%

Epigenetic switches of tobacco transgenes associate with transient redistribution of histone marks in callus culture

2013

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“…To date, different proteins and enzymes, partici pating at different stages of the transgene silencing have been identified [4,5,8]. However, the mecha nisms triggering failure or reactivation of the transgene expression simultaneously in all cells of one somatic tissue, are still unknown.…”

Section: Modifiers Of Mosaic Transgene Expression Patterns In Plantsmentioning

confidence: 99%

“…More detailed analysis of molecular genetic mechanisms of transcriptional and posttran scriptional transgene silencing is reviewed elsewhere [4,5].…”

Section: Introductionmentioning

confidence: 99%

Mosaic patterns of transgene expression in plants

2012

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“…Using this expression system for producing recom binant proteins, including plant vaccines, is still ham pered by relatively low levels of transgene expression, which is, as a rule, less than 1% of total soluble protein (TSP) and also by its variability in different plant organs and tissues within a single plant and in different plants. Most often, the variability in expression of the transgene is due to the random nature of its insertion into the nuclear genome (effect of position) and may be associ ated with partial or complete transgene inactivation [27,28]. Experts believe that the use of plant expression sys tems for obtaining plant vaccines is economically bene ficial at the level of expression of a target gene, which allows the accumulation of recombinant protein in an amount not less than 1% of TSP [29].…”

Section: Transgenic Plantsmentioning

confidence: 99%

State of research in the field of the creation of plant vaccines for veterinary use

Permyakova

Уварова

Дейнеко

2015

Russ J Plant Physiol

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Transgenic plants as an alternative of costly systems of recombinant immunogenic protein expres sion are the source for the production of cheap and highly efficient biotherapeuticals of new generation, including plant vaccines. In the present review, possibilities of plant system application for the production of recombinant proteins for veterinary use are considered, the history of the "edible vaccine" concept is briefly summarized, advantages and disadvantages of various plant systems for the expression of recombinant immu nogenic proteins are discussed. The list of recombinant plant vaccines for veterinary use, which are at differ ent stages of clinical trials, is presented.Abbreviations: TMV-tobacco mosaic virus; TSP-total soluble protein.

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Transcriptional gene silencing in plants

Cited by 12 publications

References 56 publications

Epigenetic switches of tobacco transgenes associate with transient redistribution of histone marks in callus culture

Epigenetic switches of tobacco transgenes associate with transient redistribution of histone marks in callus culture

Mosaic patterns of transgene expression in plants

State of research in the field of the creation of plant vaccines for veterinary use

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