Epigenetic inactivation of chalcone synthase-A transgene transcription in petunia leads to a reversion of the post-transcriptional gene silencing phenotype
Epigenetic inactivation of chalcone synthase-A transgene transcription in petunia leads to a reversion of the post-transcriptional gene silencing phenotype
复制标题
DOI：
10.1093/pcp/pcm028
复制
发表时间：
2007-04-01
影响因子：
4.9
通讯作者：
Hellens, Roger P.
中科院分区：
文献类型：
--
作者：
Kanazawa, Akira;O'Dell, Michael;Hellens, Roger P.
表现出白色开花表型的矮牵牛植物作为脉酮合酶转基因诱导的沉默的结果，偶尔会产生产生具有野生型色素沉着的花的回复突变分支。转录启动试验证实了白色花的产生是由转录后基因沉默（PTGS）引起的，并表明转基因转录在回复体植物中受到抑制，提供了PTGS的诱导依赖于转录速率的证据。转基因的转录抑制与CpG、CpNpG和CpNpN位点的胞嘧啶甲基化相关，并且通过5-氮杂胞苷或阿司他丁A处理恢复表达。这些结果表明PTGS系中发生了表观遗传变化，并且这些变化干扰转基因转录的起始，导致PTGS表型的逆转。
Petunia plants that exhibit a white-flowering phenotype as a consequence of chakone synthase transgene-induced silencing occasionally give rise to revertant branches that produce flowers with wild-type pigmentation. Transcription run-on assays confirmed that the production of white flowers is caused by post-transcriptional gene silencing (PTGS), and indicated that transgene transcription is repressed in the revertant plants, providing evidence that induction of PTGS depends on the transcription rate. Transcriptional repression of the transgene was associated with cytosine methylation at CpG, CpNpG and CpNpN sites, and the expression was restored by treatment with either 5-azacytidine or trichostatin A. These results demonstrate that epigenetic changes occurred in the PTGS line, and these changes interfere with the initiation of transgene transcription, leading to a reversion of the PTGS phenotype.