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M. De Neve S. De Buck C. De Wilde H. Van Houdt I. Strobbe A. Jacobs M. Van Montagu A. Depicker 《Molecular & general genetics : MGG》1999,260(6):582-592
The stability of antibody and Fab expression was assessed in five different homozygous transgenic Arabidopsis lines. Each of these lines showed silencing of the transgenes that encode the antibody polypeptides, leading to instability
of antibody production. However, each line had a different and specific instability profile. The characteristic variation
in the level of antibody accumulation in each line as a function of developmental stage indicated that the T-DNA integration
pattern played a role in triggering silencing, and also that the history and the integration position of simple transgene
loci can influence the susceptibility to epigenetic silencing. In different lines with low antibody accumulation levels, methylation
was found either in the promoter alone, in both the promoter and the transcribed region, in the transcribed region only, or
in the transcribed region and downstream sequences. In conclusion, our data suggest that epigenetic effects result in different
transgene expression profiles in each of the five Arabidopsis lines analyzed.
Received: 27 July 1998 / Accepted: 12 October 1998 相似文献
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Mingmin Zhao David San León Ma. Otilia Delgadillo Juan Antonio García Carmen Simón‐Mateo 《The Plant journal : for cell and molecular biology》2014,79(3):440-452
We used bisulfite sequencing to study the methylation of a viral transgene whose expression was silenced upon plum pox virus infection of the transgenic plant and its subsequent recovery as a consequence of so‐called virus‐induced gene silencing (VIGS). VIGS was associated with a general increase in the accumulation of small RNAs corresponding to the coding region of the viral transgene. After VIGS, the transgene promoter was not methylated and the coding region showed uneven methylation, with the 5′ end being mostly unmethylated in the recovered tissue or mainly methylated at CG sites in regenerated silenced plants. The methylation increased towards the 3′ end, which showed dense methylation in all three contexts (CG, CHG and CHH). This methylation pattern and the corresponding silenced status were maintained after plant regeneration from recovered silenced tissue and did not spread into the promoter region, but were not inherited in the sexual offspring. Instead, a new pattern of methylation was observed in the progeny plants consisting of disappearance of the CHH methylation, similar CHG methylation at the 3′ end, and an overall increase in CG methylation in the 5′ end. The latter epigenetic state was inherited over several generations and did not correlate with transgene silencing and hence virus resistance. These results suggest that the widespread CG methylation pattern found in body gene bodies located in euchromatic regions of plant genomes may reflect an older silencing event, and most likely these genes are no longer silenced. 相似文献
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